ME 602 Computational Fluid Dynamics and Heat Transfer FINAL EXAM refresher

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ME 602

1. Convert 950R to K a. 490.33 K b. 596.44 K c. 220.33 K d. 527.44 K* 2. Find the pressure at the 80 fathom depth of water in kpag. a. 1,435.17 kpag* b. 1,693.17 kpag c. 1,742.35 kpag d. 1,293.35 kpag 3. Helium gas is compressed in an adiabatic compressor from an initial state of 14 psia and 50oF to a final temperature of 320oF in a reversible manner. Determine the exit pressure of Helium. a. 54.5 psia b. 40.49 psia* c. 35.8 psia d. 69.8 psia 4. 3.0 lbm of air are contained at 25 psia and 100 °F. Given that Rair = 53.35 ft-lbf / lbm-°F, what is the volume of the container? a. 30.7 ft3 b. 17.5 ft3 c. 24.89 ft3* d. 22.3 ft3 5. A perfect gas has a value of R= 58.8 ft-lb/lb-R and K= 1.26. if 20 Btu are added to 10 lbs of his gas at constant volume when initial temperature is 90 degF find the final temperature. a. 177 degF b. 97 degF* c. 143 degF d. 85 degF 6. A spherical balloon with a diameter of 6 m is filled with helium at 20 deg. C and 200 Kpa. Determine the mole number. a. 17.56 Kmol b. 25.39 Kmol c. 9.28 Kmol* d. 19.61 Kmol 7. Find the mass of carbon dioxide having a pressure of 20 psia at 200F with 10ft^3 volume. a. 1.34 lbs b. 1.04 lbs c. 1.24 lbs * d. 1.14 lbs 8. Steam turbine is receiving 1014 lbm/hr of steam, determine the horsepower output of the turbine if the work done by steam is 255 btu/lbm a. 102 HP* b. 462.8 HP c. 200 HP d. 6003.7 HP 9. Find the work possess for a Helium gas at 200C

A. 609 KJ/kg * B. 168 KJ/kg C. 229 KJ/kg D. 339 KJ/kg 10. The gain of entropy during isothermal nonflow process of 5 lb of air at 60 is 0.462 Btu/R. Find the V1/V2.

A. 3.85 B. 0.259* C. 1.0 D. 0.296 11. Oil flow through a 16 tubes on a single cooler with a velocity of 2 m/s, the internal diameter of the tube is 30mm and oil density is 0.85gm/ml. Find the volume flow in liters per sec.

A. 22.62 * B. 32.22 C. 62.22 D. 42.62 12. 438K is _____˚F a 213˚F b 329˚F* c 113˚F d 1156˚F 13. Find the mass of ammonia (NH3) in a 5m3 vessel having a pressure of 120kpa and 20˚C. a 4.187 kg* b 3.763 kg c 2.837 kg d 1.563 kg 14. Find the specific volume of air having 90˚F and 15 psi condition. a 11.57 ft3/lb b 13.57 ft3/lb c 15.57 ft3/lb d 17.57 ft3/lb 15. Air at 4m3 and 120kpa undergoes an isothermal process until the pressure is 400 kpa. Find the final volume. a 1.2 m3 b 1.5 m3 c 1.8 m3 d 2.1 m3 16. A steam enters the system with enthalpy of 3300 KJ/kg at 200m/s and leaves with enthalpy at 2700 KJ/kg at 80m/s. Find the work output of the turbine. a 616.8 KJ/kg* b 313.9 KJ/kg c 442.2KJ/kg d 978 KJ/kg 17. Two pounds per second steam enters the turbine at 500ft/s with 600 Btu/lb enthalpy and leaves at 200 ft/s and 500Btu/lb. If heat loss is 5000Btu/hr, find the horsepower output of the turbine. a 458.14 b 292.92* c 478.14

d 488.14 18. In a constant temperature, closed system process, 120 Btu of heat is transferred to the working fluid at 80˚F. What is the change of entropy of the working fluid, Kj/kg-K? a 0.422* b 0.522 c 0.622 d 0.722 19. Compute the mass of a 2m^3 propane at 280 kpa and 40˚C. a.

6.47 kg b.

5.1 kg c.

10.20 kg d.

9.47 kg* 20. Find the equivalent 36˚F temperature change in ˚C. a 2.22˚C b 3.33˚C c 20˚C* 21. A certain boiler has a pressure of 200 psi. If barometric pressure is 745 mm of Hg, find the absolute pressure in kpa. a 1652.45 b 1823.21 c 3846.78 d 1477.90* 22. A tank contains water having a height of 10m and oil (SG=0.9) with 4m above water surface. Find the pressure of water at the bottom of the tank. a 143.42 kpag b 123.42 kpag c 133.42 kpag* d 113.42 kpag 23. If a 1000 kg body is moving at 5 m/s, what is the kinetic energy? a 150 KJ b 18 KJ c 175 KJ d 12.5KJ 24. A certain fluid has an enthalpy 1800 KJ/kg and 500 KJ/kg work flow. Find the internal energy. a 2000 KJ/kg b 1400 KJ/kg c 1600 KJ/kg d 1300 KJ/kg* 25. Ten kilogram of water is mixed with 12 kilogram of alcohol (SG=0.9). what is the specific gravity of the mixture, assuming that the two fluids mix completely? a 0.875 b 0.987 c 0.765 d 0.943* d 30˚C

1. 200g of water are heated from 5C to 100C and vaporized at a constant pressure. The heat of vaporization of water at 100C is 539.2 cal/g. The heat capacity at constant pressure, Cp is 1.0 cal/gK. Determine the total change in entropy. a. 248.2 cal/K b. 298.1 cal/K c. 348.0 cal/K* d. 398.2 cal/K

2. Steam at 1000 lbf/ft2 pressure and 300°R has a specific volume of 6.5 ft3/lbm and a specific enthalpy of 9800 lbf-ft/lbm. Find the internal energy per pound mass of steam. a. 2500 lbf-ft/lbm b. 3300 lbf-ft/lbm* c. 5400 lbf-ft/lbm d. 6900 lbf-ft/lbm

3. One kilogram of water (cv = 4.2 kJ/kg-K) is heated by 300 BTU of energy. What is the change in temperature, in K? a. 17.9 K b. 72.4 K c. 74.8 K d. 75.4 K*

4. Shaft work of -15 BTU/lb and heat transfer of -10 BTU/lb change enthalpy of a system by: a. -25 BTU/lb b. -15 BTU/lb c. -10 BTU/lb d. +5 BTU/lb*

5. A mixture at 14.7 psia and 68F that is 30% weight CO 2 (m wt=44) and 7% wt. N2 (m wt=28) has a partial pressure of CO2 in psia that is nearest to: a. 2.15

b. 3.15 * c. 6.82 d. 7.32 6.

A perfect gas has a value of R= 58.8 ft-lb/lb-R and K= 1.26. if 20 Btu are added to 10 lbs of his gas at constant volume when initial temperature is 90 degF find the final temperature.

a. 97 degF* b.

104 degF c.

164 degF d.

186 degF 2.

A spherical balloon with a diameter of 6 m is filled with helium at 20 deg. C and 200 Kpa. Determine the mole number. a.

9.28 Kmol* b.

10.38 Kmol c.

11.28 Kmol d.

13.28 Kmol 3.

A one cubic meter container contains a mixture of gases composed of 0.02 kg/mol of oxygen and 0.04 kg-mol helium at a pressure of 220 Kpa. What is the temperature of this ideal gas mixture in degrees kelvin? a.

441* b.

350 c.

400 d.

460 4.

Convert 750R to K a.

390.33 K b.

396 K c.

420.33 K d.

416.33 K* 5. a. b. c. d.

Find the mass of 10 quartz of water 10.56 kg 9.46 kg * 11.6 kg 8.46 kg

6.

Steam leaves an industrial boiler at 827.4 kPa and 171.6C. A portion of the steam is passed through a throttling calorimeter and is exhausted to the atmosphere when the calorimeter pressure is 101.4 kPa. How much moisture does the steam leaving the boiler contain if the temperature of the steam at the calorimeter is 115.6C? At 827.4 kPa (171.6C): hf = 727.25 kJ/kg, hfg = 2043.2 kJ/kg From table 3: at 101.4 kPA and 115.6C:

h2 = 20707.6 kJ/kg

a.

3.78% b. 3.08%*

c. 5.56%

d. 2.35%

7.

One kg of steam at 121C and 10% moisture undergoes a constant volume until the pressure becomes 0.28 Mpa. Determine the final temperature. a.

200.4Cb. 374.6C

c. 206.5C*

d. 873.4C

8.

A cylinder and piston arrangement contains saturated water vapor at 110C. The vapor is compressed in a reversible adiabatic process until the pressure is 1.6 Mpa. Determine the work done by the steam per kg of water. a.

-637 kJb. -509 kJ

c. -432 kJ*

d. -330 kJ

9.

A turbine has an available enthalpy of 3300 kJ/kg in a Rankine cycle. The pump work has also 25 kJ/kg. For flow of 3 kg/s, find the system output. a.

5961 kW

b. 6081 kW

c. 6340 kW

d. 9825 kW*

10.

A rankine cycle has a steam throttle condition of 4 Mpa and 400C. The turbine exhaust is 1 atm, find the cycle efficiency. a.

23.23%

b. 27.06%*

c. 34.23%

d. 43.23%

7. How many degree Celsius is 80 degrees Fahrenheit? a. 26.67* b. 86.4 c. 33.33 d. 16.34

8. How many horsepower is 746 kW? a.

1 HP

b.

100 HP

c.

74.6 HP

d.

1000 HP *

9. How many grams is 8 ounce? a. 226.79 grams* b. 210.68 grams c. 198.76 grams d. 120.68 grams 10. How many cubic meters is 100 gallons of liquid? a. 0.1638 cu. meters b. 1.638 cu. meters c. 0.3785 cu. meters * d. 1.3796 cu. meters

11. A pressure reading of 35 psi in kPa abs is: a. 457.3 b. 724.2 c. 272.4 d. 342.72 * 26. A Brayton cycle has a pressure ratio of 9. Find the cycle efficiency. a 43.62% b 46.62%* c 40.62% d 49.62% 27. Find the rankine cycle thermal efficiency of a steam plant with the following enthalpies in KJ/kg: entering turbine = 3100, leaving turbine = 2400, entering pump = 140, leaving pump = 180. a 52.5% b 41.7% c 32.1% d 22.6%* 28. Steam leaves an industrial boiler at 827.4 kPa and 171.6C. A portion of the steam is passed through a throttling calorimeter and is exhausted to the atmosphere when the calorimeter pressure is 101.4 kPa. How much moisture does the steam leaving the boiler contain if the temperature of the steam at the calorimeter is 115.6C? At 827.4 kPa (171.6C): hf = 727.25 kJ/kg, hfg = 2043.2 kJ/kg From table 3: at 101.4 kPA and 115.6C: h2 = 20707.6 kJ/kg a. 4.78% b. 10.56% c. 7.58% d. 3.08%*

29. In an ideal Brayton cycle has a net work output of 150KJ/kg and backwork ratio of 0.4. If both the turbine and the compressor had an isentropic efficiency of 80%, the net work output of the cycle would be.

A. 50KJ/kg B. 75KJ/kg * C. 98KJ/kg D.120KJ/kg 30. What is the approximate value of temperature of water having enthalpy of 208 Btu/lb?

A. 138.67 ˚C B. 115.55 ˚C * C. 258.67 ˚C D. 68.67 ˚C 31. At 1.3MPa, mixture steam and water has an entropy of 3KJ/kg-oK. Find the enthalpy of the mixture.

At 1.3MPa: sf = 2.2515, sg = 6.4953, hf = 814.93, hfg = 1972.7 a 1627.71 KJ/kg b 1533.33 KJ/kg c 1234.45 KJ/kg d 1162.40 KJ/kg* 32. Is applied to propulsion of vehicles because of certain practical characteristics.

A. Diesel cycle B. Otto cycle C. Carnot cycle D. Brayton cycle* 33. A dual cycle has an initial temperature of 30 ˚C. The compression ratio is 6 and the heat addition at constant volume process is 600 KJ/kg. If cut-off ratio is 2.5, find the maximum temperature of the cycle.

A. 3638.50 ˚C B. 3365.50 ˚C * C. 3565.50 ˚C D. 3965.50 ˚C 34. In stirling process the heat added is added during?

A. isobaric process B. isentropic process C. isothermal process* D. isometric process 35. What is the approximate value of temperature of water having enthalpy of 208 Btu/lb?

A. 138.67 ˚C B. 115.55 ˚C * C. 258.67 ˚C D. 68.67 ˚C 36. A diesel cycle has an initial temperature of 27˚C. If the cut-off ratio is 2.5 and compression ratio is 12, find the maximum temperature of the cycle. a 1634.4˚C b 1753.44˚C* c 2010.3˚C d 1983.4˚C 37. A diesel cycle has a temperature after isentropic expansion of 100˚C. If expansion ratio is 4, find the maximum temperature of the cycle.

a 376.43˚C* b 366.43˚C c 356.43˚C d 346.63˚C 38. A diesel cycle has a compression ratio of 8 and an initial condition of air at 31˚C. If maximum temperature is 1400˚C, find the cycle efficiency. a 43.40% b 46.60%* c 56.34% d 51.27% 39. Helium gas is an ideal Otto cycle is compressed from 20oC and 2L to 0.25L and its temperature increases by an additional 800oC during the addition process. The temperature of helium before the expansion process is: A. 1700˚C * B. 1440˚C C. 1240˚C D. 880˚C 40. In an ideal Brayton cycle has a net work output of 150KJ/kg and backwork ratio of 0.4. If both the turbine and the compressor had an isentropic efficiency of 80%, the net work output of the cycle would be.

A. 50KJ/kg B. 75KJ/kg * C. 98KJ/kg D.120KJ/kg 41. A Brayton cycle has an initial temperature of 30˚C. If compression ratio of compressor is 8, find the compressor work in KJ/kg. a 363.11 KJ/kg b 373.11 KJ/kg c 383.11 KJ/kg d 393.11 KJ/kg* 42. A Brayton cycle has an initial air condition of 80˚F and maximum temperature of 800˚F. If pressure ratio is 8, find the backwork ratio. a 0.6763 b 0.7763* c 0.8763 d 0.9763 43. What is the percentage by mass of nitrogen in air which has 25% oxygen and 75% nitrogen by volume? a 78.5 b 76.7 c 80.2 d 72.41 * 44. A diesel cycle has a cut-off ratio of 2.2 and compression ratio of 10. Find the cycle efficiency. a 55.10% b 59.73% c 52.23%* d 62.37% 45. Is applied to propulsion of vehicles because of certain practical characteristics.

A. Diesel cycle B. Otto cycle C. Carnot cycle D. Brayton cycle* 46. Regenerative with feed heating cycle with infinite number of feed water heaters thus efficiency is equal to? a. Otto cycle b. Stirling cycle c. Erricson cycle d. Carnot cycle * 47. Consider two Carnot heat engines operating in series. The first engine receives heat from the reservoir at 2500oK and rejects the waste heat to another reservoir at temperature T. The second engine receives heat by the first one, convert some of it to work, and rejects the rest to a reservoir at 300oK. If thermal efficiencies of both engines are the same, determine the temperature T. a. 849K * b. 578 K c. 763 K d. 976 K 48. An Otto cycle has a compression ratio of 8. Find the pressure ratio during compression. a. 18.38 * b. 16.38 c. 14.38 d. 12.38 49. A Diesel cycle has a cut off ratio of 2.5 and expansion ratio of 4. Find the clearance of the cycle.

A. 9.11 % B. 5.55 % C. 11.11 % * D. 15.15 % 50. A Brayton cycle has a pressure ratio of 9. Find the cycle efficiency. a. 43.62% b. 46.62%* c. 40.62% d. 49.62% 51. A turbo-charged, 16 cylinder, Vee-type diesel engine has an air consumption of 3,000 kg/hr per cylinder at rate load and speed. This air is drawn in through a filter by a centrifugal compressor directly connected to the exhaust gas turbine. The temperature of the air from the compressor is 135C and a counter flow air cooler reduces the air temperature to 45C before it goes to the engine suction heater. Cooling water enters air cooler at 30C and leaves at 40C. Calculate the log mean temperature difference.

A. 47.23C B. 87.82C * C. 43.34C D. 65.24C 52. Water is boiling at 1 atm pressure in a stainless steel pan on an electric range. It is observed that 2 kg of liquid Water evaporates in 30 mins. The rate of heat transfer to the water is: A. 2.51 KW*

B. 1.55 KW C. 2.79 KW D. 3.32 KW 53. Consider a person standing in a breezy room at 20oC. Determine the total rate of heat transfer from this person if the exposed surface area and the average outer surface temperature of the person are 1.6 m2 and 29oC, respectively, and the convection heat transfer coefficient is 6 W/m2 with emissivity factor of 0.95.

A. 86.40 watts B. 61.70 watts C. 198.1 watts D. 168.1 watts* 54. Hot gases at 280 degC flow on one side of a metal plate of 10mm thickness and air at 35 degC flows the other side. The heat transfer coefficient of the gases is 31.5 W/m^2-k and that of the air is 32 W/m^2-K. calculate the over all transfer coefficient.

A. 13.92 W/m^2-K B. 21.52 W/m^2-K C. 12.82 W/m^2-K D. 15.82 W/m^2-K* 55. Consider a person standing in a breezy room at 20 deg C. Determine the total rate transfer from this person of the exposed surface area and the average outer surface temperature of the person are 1.6 m2 and 29 deg C, repectively, and the convection heat transfer coefficient is 6 W/m2 with emissivity of 0.95.

A. 128.40 watts B. 168.0 watts* C. 89.70 watts D. 198.30 watts COMBUSTION 56. The specific gravity of oil tested at 29.4C is 0.852. Find its API in degrees.

A. 35.98 B. 37.62 C. 32.98* D. 23.54 57. A diesel engine consumed 945 liters of fuel per day at 35C. If the fuel was purchased at 15.6C and 30C API at P29.00/li, determine the cost of fuel to operate the engine per day.

A. P27,030.51* B. P44,977.50 C. P62,088.90 D. P3,984.68 58. Determine the air- fuel ratio on a molar basis for the complete combustion of octane, with theoretical amount of air.

A. 59.5 molair/molfuel* B. 49.5 molair/molfuel C. 69.5 molair/molfuel D. 39.5 molair/molfuel 59. Determine the air- fuel ratio on a mass basis for the complete combustion of octane, with theoretical amount of air.

A. 15.05 kgair/kgfuel*

B. 13.55 kgair/kgfuel C. 11.87 kgair/kgfuel D. 17.93 kgair/kgfuel 60. Methyl alcohol (CH3OH) is burned with 25% excess air. How much unburned oxygen in kg-mol-oxygen / kg-mol fuel will there be in the products if the combustion is complete?

A. 0.24 B. 0.57 C. 0.42 D. 0.37* FLUID MECHANICS 61. Is a fluid property which refers to the intermolecular attraction by which the separate particles of the fluid are held together A. Cohesion* B. Surface tension C. Adhesion D. Hypertension 62. A perfect venture with throat diameter of 1.8 inches is placed horizontally in a pipe with a 5 in inside diameter. Eighty (80) lb of water flow through the pipe each second. What is the difference between the pipe and venturi throat static pressure?

A. 29.9 lb/in2 B. 34.8 lb/in2* C. 5020 lb/in2 D. 72.3 lb/in2 63. What is the expected head loss per mile of a closed circular pipe (17 in inside diameter), friction factor of 0.03 when 3300 of water flow under pressure?

A. 38 ft* B. 3.580 ft C. 0.007 ft D. 0.64 ft 64. A rigid container is closed at one end and measure 8 in diameter by 12 in long. The container is held vertically and is slowly moved downward until the pressure in the container is 15.5 psia. What will be the depth of the water surface measure from the free water surface?

A. 22 in* B. 9.2 in C. 12 in D. 9.8 in 65. The pressure drop across a turbine is 25 psi. The flow rate is 55 gallons per minute.

Calculate the power output of the turbine.

A. 0.802 hp* B. 0.41 hp C. 1.05 hp D. 2.54 hp REFRIGERATION AND AIRCONDITIONING

66. Is the most common dryer used which consist of rotating cylinder inside which the materials flow while getting contact with hot gas. a.

Tower dryer b.

Tray dryer c.

Centrifugal dryer d.

Rotary dryer* 67. Is the ratio of the mass of water-vapor in air and the mass of air if it is saturated is called: a.

Humidity ratio b.

Mass ratio c.

Vapor ratio d.

Relative humidity* 68. The refrigerant used in the steam jet cooling system: a. Steam b. R-11 c. Ammonia d. Water* 69. A refrigerating plant circulates 23 lb Freon-12 per minute and is assume to operate on a cycle. The pressure in the evaporator coil is 50 psia, the temperature of the Freon-12 entering the compressor is 50F, the pressure in the condenser is 120 psia and the temperature of the liquid refrigerant entering the expansion valve is 86F. Enthalpies are h1=84.24 Btu/lb, h2=91.31 Btu/lb, h3=h4=27.72 Btu/lb. Calculate the refrigerating effect. a.

56.52 Btu/lb* b.

53.35 Btu/lb c.

54.45 Btu/lb d.

57.75 Btu/lb 70. A refrigerating plant circulates 23 lb Freon-12 per minute and is assume to operate on a cycle. The pressure in the evaporator coil is 50 psia, the temperature of the Freon-12 entering the compressor is 50F, the pressure in the condenser is 120 psia and the temperature of the liquid refrigerant entering the expansion valve is 86F. Enthalpies are h1=84.24 Btu/lb, h2=91.31 Btu/lb, h3=h4=27.72 Btu/lb. Calculate the capacity of plant. a.

6.5 tons* b.

7.5 tons c.

8.5 tons d.

9.5 tons 71. A refrigerating plant circulates 23 lb Freon-12 per minute and is assume to operate on a cycle. The pressure in the evaporator coil is 50 psia, the temperature of the Freon-12 entering the compressor is 50F, the pressure in the condenser is 120 psia and the temperature of the liquid refrigerant entering the expansion valve is 86F. Enthalpies are h1=84.24 Btu/lb, h2=91.31 Btu/lb, h3=h4=27.72 Btu/lb. Calculate the power required to compress the Freon-12. a.

3.83 hp* b.

4.83 hp c.

3.33 hp d.

2.83 hp 72. A refrigerating plant circulates 23 lb Freon-12 per minute and is assume to operate on a cycle. The pressure in the evaporator coil is 50 psia, the temperature of the Freon-12 entering the compressor is 50F, the pressure in the condenser is 120 psia and the

temperature of the liquid refrigerant entering the expansion valve is 86F. Enthalpies are h1=84.24 Btu/lb, h2=91.31 Btu/lb, h3=h4=27.72 Btu/lb. Calculate the COP. a.

7.99* b.

8.99 c.

9.99 d.

10.99 73. A twin cylinder ammonia compressor with volume displacement of 14,726 cm3 operates at 300 rpm. Condenser and evaporator pressure are 1200 kPa and 227 kPa respectively.

Specific volume of refrigerant at the entrance of compressor is 528.26 L/kg. Compression process is polytrophic with a 1.20 and clearance factor of compressor is 2%. Determine horsepower required. a. 80hp* b. 60hp c. 40hp d. 120hp 74. An ammonia simple saturation cycle operates with a suction pressure of 291.6 kPa and a condenser pressure of 1204 kPa develops 15 tons of refrigeration. Determine the theoretical horsepower of the compressor. The following enthalpies have been found at the condenser entrance = 1653 kJ/kg, exit = 346.6 kJ/kg, compressor entrance 1450.2 kJ/kg, exit = 1653 kJ/kg. a. 13 hp* b. 15 hp c. 18 hp d. 23 hp 75. A refrigeration system consumed 28,800 kw-hr per month of energy. There are 20% of energy is lost due to cooling system of the compressor and motor efficiency is 90%. If COP of the system is 6, find the tons of refrigeration of the system. a. 40.32 TR b. 42.28 TR c. 45.97 TR d. 49.15 TR* 76. A reversed Carnot cycle has a refrigerating COP of 2.5. Determine the ratio TH/TL? A.1.5 B.1.25 C.1.4* D.1.55 77. Consider a refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigeration has a COP of 1.3 and the cost of electricity is 8 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed. a. P43.59 b. P45.59 c. P47.59. d. P49.59* 78. A Carnot refrigerator operates in a room in which the temperature is 25C and consumes 2 kW of power when operating. If the food compartment of the refrigerator is to be maintained at 3C, determine the rate of heat removal from the food compartment.

A. 2216.8 kJ/min

B. 128.6 kJ/min C. 1504.8 kJ/min* D. 109.57 kJ/min 79. A household refrigerator with EER 8.0 removes heat from the refrigerated space at a rate of 90 kJ/min. Determine the rate of heat transfer to the kitchen air.

A.69.65 kJ/min B.148.35 kJ/min C.80.46 kJ/min D.128.46 kJ/min* 80. The power requirement of a Carnot refrigerator in maintaining a low temperature region at 300 K is 1.5 kW per ton. Find the heat rejected. a. 5.02 kW* b. 3.12 kW c. 7.42 kW d. 4.30 kW 81. An ammonia ice plant operates between a condenser temperature of 35C and evaporator of -15C. It produces 10 metric ton of ice per day from water at 30C to ice at -5C. Assuming simple saturation cycle, determine the horsepower of the motor if the adiabatic efficiency of the compressor ec = 0.851 and mechanical efficiency em = 0.95. The specific heat of ice is 2.094 kJ/kg-C and the latent heat is 335 kJ/kg. From the table of ammonia the following enthalpies are: condenser entrance = 1703 kJ/kg, exit = 366.1 kJ/kg; compressor entrance = 1443.9 kJ/kg, exit = 1703 kJ/kg. a. 17.58 hp b. 21.9 hp* c. 23.4 hp d. 25.6 hp 42. The mass of an outside air at 50°C in an air conditioning unit is 60 kg. Find the temperature after mixing with 40 kg with recirculated air at 35°C. a. 35°C b. 44°C* c. 59°C d. 33°C 43. Find the sensible heat factor of an air-conditioning unit having a sensible heat load of 60 kW and latent heat load of 20 kW. a. 75%* b. 60% c. 55% d. 95% 44. A coil as an inlet temperature of 70F and outlet of 80F. If the mean temperature of the coil is 130F, find the bypass factor of the coil. a 0.28 b 1.20 c 0.81 d 0.83* 45. Compute the Humidity Ratio of air at 62 percent relative humidity and 34°C when the barometric pressure is 101.325 kPa. a. 0.051 kgvapor/kgdry air b. 0.042 kgvapor/kgdry air

c. 0.032 kgvapor/kgdry air d. 0.021 kgvapor/kgdry air* 46. In an air conditioning system, if the re-circulated air is three times the outside air and the mass of supply air is 20 kg/s, what is the mass of the outside air? a. 2 kg/s b. 4 kg/s c. 5 kg/s* d. 6 kg/s 47. Re-circulated air of 10 kg/s with 53 KJ/kg dry air enthalpy and outside air of 4 kg/s with 90KJ/kg dry air enthalpy enters the conditioning unit. Determine the air conditioning capacity of air conditioning apparatus if the supply enthalpy to conditioned space is 42 kJ/kg dry air. a. 184 KW b. 204 KW* c. 302 KW d. 154 KW 48. Water enters the cooling tower at 45C. The approximate leaving water temperature is 30C. If the atmospheric condition is 25C wet bulb, determine the cooling effectiveness. a 75%* b 65% c 55% d 85% 49. Water enters the cooling tower at 45C. The approximate leaving water temperature is 30C. If the atmospheric condition is 25C wet bulb, determine the approach. a 5C* b 10C c 15C d 20C 50. Water enters the cooling tower at 45C. The approximate leaving water temperature is 30C. If the atmospheric condition is 25C wet bulb, determine the range. a.

15C* b.

20C c.

5C d.

30C INDUSTRIAL PLANT ENGINEERING 51. An air compressor takes in 50 ft3/min of air at 14.7 psia and 60F. The air is discharge at 100 psia and 260F. Find the mass flow rate of air. a.

2.45 lb/min b.

3.82 lb/min* c.

4.68 lb/min d.

5.72 lb/min 52. An air compressor takes in 50 ft3/min of air at 14.7 psia and 60F. The air is discharge at 100 psia and 260F. Find the mass flow rate of air. a.

9.18 ft3/min b.

10.18 ft3/min* c.

11.18 ft3/min d.

12.18 ft3/min

53. An axial flow compressor discharges 900 lb/min of air. Inlet conditions are 14.7 psia and 50F, while the actual discharge conditions are 162 psia and 648F. Calculate the capacity. a.

11,557 ft3/min* b.

10,557 ft3/min c.

12,557 ft3/min d.

13,557 ft3/min 54. An axial flow compressor discharges 900 lb/min of air. Inlet conditions are 14.7 psia and 50F, while the actual discharge conditions are 162 psia and 648F. Calculate the isentropic compression efficiency. a.

79% b.

90% c.

84%* d.

75% 55. An axial flow compressor discharges 900 lb/min of air. Inlet conditions are 14.7 psia and 50F, while the actual discharge conditions are 162 psia and 648F. Calculate the isentropic compression power. a.

(-)2333 hp (on) b.

(-)2777 hp (on) c.

(-)2132 hp (on) d.

(-)2558 hp (on)* 56. An axial flow compressor discharges 900 lb/min of air. Inlet conditions are 14.7 psia and 50F, while the actual discharge conditions are 162 psia and 648F. Calculate the actual compression power. a.

(-)2345 hp (on) b.

(-)1895 hp (on) c.

(-)2678 hp (on) d.

(-)3045 hp (on)* 57. Type of solid injection that use single pump supplies fuel under high pressure to a fuel header a. Common rail injection* b. Distributor system c. Individual pump injection system d. Single rail injection 58. The pitot static tube measure a. The static pressure* b. The gage pressure c. The total pressure d. The dynamic pressure 59. A fan pressure of 2.54 cm of water at 1.42 m3 per second of air at static pressure of 2.54 cm of water through a duct 300 mm diameter and discharges it through a duct 275 mm diameter. Determine the static fan efficiency if total fan mechanical is 75% and air measured at 25 and 60 mm Hg. A. 53.69% * B. 48.32% C. 59.44% D. 62.13%

60. A fan is powered by a 0.5 hp motor and delivers air at a rate of 85 m3/min. Determine the highest value for the average velocity of air mobilized by the fan. The density of air is 1.18 kg/m3.

A. 24.27 m/s B. 29.66 m/s C. 18.99 m/s D. 21.13 m/s* 61. An air compressor delivers 0.23m3/s of water at 100 kpa and discharge to 650 kPa. Find the air power. a.

36.35 kw b.

45.23 kw c.

40.23 kw d.

56.92 kw* 62. A single stage compressor has an initial pressure of 98 kpa and compresses to 800 kpa with suction volume 0.2m3/s. Using PV1.34=C, find the percent decrease in power due to two staging. a.

14.23% b.

10.23% c.

18.34% d.

13.23%* 63. A fan has a power output of 100kw. The fan efficiency is 70%. Find the horsepower output of the motor needed to drive the fan. a.

142.86 b.

191.50* c.

123.45 d.

165.56 64. A fan has a static head of 150 mm of water gage with air velocity of 20 m/s. find the air power if air condition is 26C and 100kpa with volume flow of 5m3/s. a.

7.45 kw b.

5.23 kw c.

8.52 kw* d.

6.34 kw 65. The volumetric efficiency of a pump is 90%, what is the slip? a. 0.23 c. 0.092 b. 0.0422 d. 0.10* 66. A reciprocating pump has 380 mm x 430 mm cylinder running at 360 rpm. If percent slip is 8%, find the volumetric efficiency of the pump. a.

92%* b.

90% c.

94% d.

88% 67. Steam flows through a nozzle at 400oC and 1 Mpa (h = 3263.9 KJ/kg) with velocity of 300 m/s. Find the stagnation enthalpy.

A. 3309 KJ/kg* B. 3193 KJ/kg C. 3425 KJ/kg D. 3090 KJ/kg

68. A pump delivers 1000 gallons per minute of water at 30 ft elevation. The suction pressure is 5 psi and discharge pressure is 20 psi. Find the power rating of motor to be use if pump efficiency is 75%. a.

81.23 hp b.

21.78 hp* c.

34.23 hp d.

43.23 hp 69. Carbon dioxide flows through a nozzle with a speed of 400 m/s. Compute the dynamic temperature.

A. 92.56K B. 94.56K * C. 96.56K D. 98.56K 70. A 3-stages air compressor compresses air from 100 kpa to 700 kpa. Find the intercooler pressure between the 2nd and 3rd stage.

A. 398.66 kpa B. 324.77 kpa C. 365.88 kpa* D. 425.55 kpa 71. An air compressor has a power of 40 kw at 4 % clearance. If clearance will increase to 70 %, what is the new power?

A. 65 kw B. 50 kw C. 53kw D. 40 kw* 72. A boiler requires 90,000 m3/hr of standard air. The mechanical efficiency of fan to be installed is 65%. Determine the size of driving motor assuming fan can deliver a total pressure of 150mm of water gage.

A. 56.6 KW* B. 78.5 KW C. 45.5 KW D. 23.5 KW 73. At 1.2 kg/m3 air density a fan develops a brake power of 100 KW. It operates at 98 Kpa and 32°C with the same speed, what is the new brake power of the fan?

A. 68.4 KW B. 36.7 KW C. 67.5 KW D. 93.3 KW* 74. A fan has a suction pressure of 30mm water vacuum with air velocity of 3m/sec. The discharge has 150 mm of water gage and discharge velocity of 7m/sec. Determine the total head of fan if air density is 1.2 kg/m3.

A. 150 m B. 152 m* C. 154 m D. 156 m 75. A 50 KW motor is used to drive a fan that has a total head of 110 m. If fan efficiency is 70%, what is the maximum capacity of the fan using standard density of air?

A. 27 m3/sec*

B. 29 m3/sec C. 31 m3/sec D. 33 m3/sec POWER PLANT ENGINEERING 76. At the beginning of the compression stroke an ideal Otto cycle has an air pressure of 15 psia, a temperature of 75F and a specific volume of 13.2 cubic feet per pound. At the end of compression the specific volume is 1.76 cubic feet per pound. The heat supplied to the cycle is 325 Btu/lb. Calculate the compression ratio. a.

6.5 b.

7.5* c.

8.5 d.

9.5 77. One pound of air at 100F is mixed with another pound of air at 40F. The mixing process is constant pressure with constant specific heat. Calculate the final mixture temperature. a.

70F* b.

80F c.

90F d.

100F 78. One pound of a certain working substance receives 100 Btu of heat at a constant temperature of 2000R. Calculate the change of entropy for the substance. a.

0.05 Btu/lb-R* b.

0.03 Btu/lb-R c.

0.07 Btu/lb-R d.

0.01 Btu/lb-R 79. An Otto Cycle, with a 7 to 1 compression ratio, has 320 Btu/lb of heat supply. At the beginning of the compression process the pressure and temperature are 14.7 psia and 60F. Assuming constant specific heat, calculate the peak temperature. a.

2542F* b.

2387F c.

2785F d.

2132F 80. A Diesel cycle has a 16 to 1 compression ratio and a peak cycle temperature of 2912R. Conditions at the beginning of compression are 14.7 psia and 60F. Assuming constant specific heat determine the peak pressure. a.

696 psi b.

714 psi* c.

735 psi d.

777 psi 81. A Brayton cycle with a pressure ratio of 6 has compressor inlet conditions of 70F and 14.7 psia. The turbine inlet temperature is equal to 1500F. Calculate the isentropic compressor discharge temperature. a.

898.3 R b.

823.8 R c.

884.3 R* d.

853.8 R 82. A Rankine steam power cycle operates with steam at 600 psia and 850F from the boiler and a condenser pressure of 1 inch of mercury absolute. Enthalpies are h4=49.4Btu/lb,

h1=1435.4 Btu/lb, s1=s2=1.6559 Btu/lb-R, h2=890.0Btu/lb, h3=47.1 Btu/lb, s4=s3=0.09146 Btu/lb-R. Determine the pump work. a.

2.3 Btu/lb* b.

4.1 Btu/lb c.

8.6 Btu/lb d.

5.8 Btu/lb 83. The indicated thermal efficiency of a two stroke diesel engine is 60%. If the friction power is 15% of the heat generated, determine the brake thermal efficiency of the engine. a. 40% b. 60% c. 75% d. 45%* 84. The specific speed of turbine is 85 rpm and running at 450 rpm. If the head is 20 m and generator efficiency is 90%, what is the maximum power delivered by the generator? a. 563.91 KW b. 835.56 KW* c. 432.18 KW d. 782.19 KW 85. In Francis turbine, the pressure gage leading to the turbine casing reads 380 Kpa. The velocity of water entering the turbine is 8 m/sec, if net head of the turbine is 44 m, find the distance from center of spiral casing to the tailrace.

A. 2.0 m* B. 1.5 m C. 3.0 m D. 5.5 m 86. A turbine has a mechanical efficiency of 93%, volumetric efficiency of 95% and total efficiency of 82%. If effective head is 45 m, find the total head.

A. 32.73 m B. 45.89 m C. 41.76 m* D. 35.88 m 87. Steam turbine is receiving 1014 lbm/hr of steam, determine the horsepower output of the turbine if the work done by steam is 255 Btu/lbm A. 102 hp* B. 462.7 hp C. 200 hp D. 6002.7 hp 88. An engine-generator rated 9000 KVA at 80% power factor, 3 phase, 4160 V has an efficiency of 90%. If overall plant efficiency is 28%, what is the heat generated by the fuel.

A. 25,714 KW * B. 27,777 KW C. 22,222 KW D. 15,532 KW 89. A 50 MW power plant has an average load of 31,500 KW and a factor of 70%. Find the reserve over peak.

A. 4 MW

B. 3 MW C. 5 MW* D. 6 MW 90. The heating surface are of water tube boiler is 200 m2, what is the equivalent rated boiler horsepower?

A. 217 Hp B. 2365.93 Hp C. 200 Hp D. 219.78 Hp* 91. The rated boiler horsepower of a fire tube boiler is 500 Hp. What is the heating surface area of the boiler?

A. 500 m2 B. 300 m2 C. 400 m2 D. 550 m2* 92. A 16,000 KW geothermal plant has a generator efficiency and turbine efficiency of 90% and 80%, respectively. If the quality after throttling is 20% and each well discharges 200,000 kg/hr, determine the number of wells are required to produce if the change in enthalpy at the entrance and exit of turbine is 500 KJ/kg.

A. 4 wells* B. 5 wells C. 6 wells D. 8 wells 93. A foundation measures 3m x 4m x 5m. Find the yd3 of stone needed for a concrete mixture of 1:2:4.

A. 65.34 B. 56.45 C. 78.48 D. 69* 94. Determine the brake power of the engine having a brake thermal efficiency of 35% and uses 250API fuel consumption of 40 kg/hr.

A. 165.84 KW B. 173.52 KW* C. 194.55 KW D. 160.67 KW 95. A diesel electric plant supplies energy for Meralco. During a 24 hour period, the plant consumed 200 gallons of fuel at 28°C and produced 3930 KW-hr. Industrial fuel used is 28°API and was purchased at P5.50 per liter at 15.6°C. What is the cost of fuel be to produce one KW-hr?

A. P1.05 * B. P1.10 C. P1.069 D. P0.30 96. A coal fired steam boiler uses 3000 kg of coal per hour. Air required for combustion is 15.5 kg per kg of coal at barometric pressure of 98.2 Kpa. The flue has temperature of 285°C and an average molecular weight of 30. Assuming an ash loss of 11% and allowable gas velocity of 7.5 m/sec, find the diameter of chimney.

A. 2.0 m

B. 1.53 m C. 1.91 m* D. 2.5 m 97. Type of turbine used to up to 300m head. a. Impulse turbine b. Francis turbine c. Propeller turbine d. Deriaz turbine* 98. Type of turbine that has diagonal flow. a. Impulse turbine b. Francis turbine c. Propeller turbine d. Deriaz turbine* 99. A type of turbine used for driving pumps, fans, and other auxiliaries in power plant commonly operate at exhaust pressure approximating atmospheric A. Tandem compound turbine B. Passout turbine C. Cross-compound turbine D. Back pressure turbine* 100.

A type of turbine employed where steam continuously extracted for process heating.

A. Back pressure turbine B. Gas turbine C. Steam turbine D. Passout turbine* A 5 cm diameter spherical ball whose surface is maintained at a temperature of 70 deg. C is suspended in the middle of a room at 20 deg. C. if the convection heat transfer coefficient is 15 W/m^2-C and the emissivity of the surface is 0.8, determine the total heat transfer from the ball. a.

23.56 watts

b.

32.77 watts*

c.

9.32 watts

d.

43.45 watts

12.

Hot gases at 280 degC flow on one side of a metal plate of 10mm thickness and air at 35 degC flows the other side. The heat transfer coefficient of the gases is 31.5 W/m^2-k and that of the air is 32 W/m^2-K. calculate the over all transfer coefficient. a.

15.82 W/m^2-K*

b.

16.82 W/m^2-K

c.

14.82 W/m^2-K

d.

12.82 W/m^2-K

13.

How many watts will be radiated from a spherical black body 15 cm in diameter at a temperature of 800 degC?

a.

5.34 KW*

b.

4.34 KW

c.

6.34 KW

d.

2.34 KW

14.

During a steady state operation, a gearbox receives 60kW through the input shaft and delivers power through the output shaft. For the gear box as the system, the rate of energy transfer is by convection. h=0.171 kW/m2K is the heat transfer coefficient, A=1m2 is the outer surface area of the gear box, Th=300K (27C) is the temperature and the outer surface, Tf=293K (20C) is the temperature of the surroundings away from the immediate vicinity if the gear box. Determine the power delivered to the output shaft in kW if the heat transfer rate is 1.2 kW. a.

99.8 KW

b.

88.8 KW

c.

68.8 KW

d.

58.8 KW*

15.

Determine the thermal conductivity of a material that is used a 4 m2 test panel, 25 mm thick with a temperature difference of 20F between surfaces. During the 4 hrs of test period, the heat transmitted is 500 kJ. a.

0.0462 W/m-C

b.

0.0723 W/m-C

c.

0.0321 W/m-C

d.

0.0195 W/m-C*

Combustion Engineering

16. What is the final temperature after compression of a Diesel Cycle if the initial temperature is 32°C and the clearance is 8%. a.

863.84 K*

b.

763.84 K

c.

963.84 K

d.

660.84 K

17. An unknown hydrocarbon fuel, CXHY, is burned with excess air containing 23.3% oxygen by mass. The volumetric analysis of the dry products of combustion is as follows: 11.94% CO2, 0.41% CO, 2.26% O2, AND 85.39% N2. Find the value of x and y, respectively. a.14.36, 44.22 b. 12.35, 33.22* c. 10.35, 32.33 d. 14.35, 32.33

18. A diesel engine takes in air at 105 kPa and 26°C subjected to a compression ratio of 19. What is the operating clearance in percent? a.5.56%* b. 6.65% c. 4.56% d. 7.60%

19. The compression ratio in a Diesel engine is 13 to 1 and the ratio of expansion is 6.5 to 1. a.54.14% b. 56.54% c. 58.04%* d. 52.14% 20. In an Otto Cycle if the compression ratio is 5.5, what is the percent clearance? a.22.22%* b. 31.21% c. 19.65% d. 25.35%

Fluid Mechanics

21. What is most nearly the terminal velocity of a 50 rnrn diameter, solid aluminum sphere falling in air? The sphere has a coefficient of drag of 0.5, the density of aluminum, Palum, is 2650 kgjm3, and the density of air, Pair, is 1.225 kgjm3 • a. 25 m/s b. 53 m/s * c. 87 m/s d.140 m/s 22. What is the static head corresponding to a flow velocity of 10 ft/sec? a.

1.55 ft*

b.

1.76 ft

c.

2.55 ft

d. 2.26 ft

23. Water flows rate along ½ in. i.d. nose at 3 gal/min. Water velocity in ft/sec is nearest to: a.2 b.5* c.11 d.20

24.

Find the depth in furlong of the ocean (SG = 1.03) if the pressure at the sea bed is 2,032.56 kpag. a.

1*

b.

2

c.

8

d.

4

25.

The work required to accelerate an 800-kg car from rest to 100 km/hr on a level road:

a.

308.6 kJ*

b.

806.2 kJ

c.

608.2 kJ

d.

386.5 kJ

Refrigeration /Airconcoditioning System 26. A refrigeration system consumed 28,800 kw-hr per month of energy. There are 20% of energy is lost due to cooling system of the compressor and motor efficiency is 90%. If COP of the system is 6, find the tons of refrigeration of the system. a.44.15 TR b. 46.15 TR c. 49.15 TR* d. 42.15 TR 27. Consider refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigeration has a COP of 1.3 and the cost of electricity is 8 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed. a. P49.59* b. P46.59 c. P42.59. d. P40.59 28. A household refrigerator that has a power input of 450 watts and a COP of 2.5 is to cool five large watermelons, 10 kg each, to 8C. If the watermelons are initially at 20C, determine how long will it take for the refrigerator cool them. The watermelons can be treated as water whose specific heat is 4.2 KJ/kg-K. a. 2120 seconds b. 2240 seconds * c. 2230 seconds d. 2250 seconds 29. The COP and the efficiency of a refrigeration cycle _______ as the vaporizing temperature increases. a.Increases*

b. decreases c.Remains the same d. constant 30. Which of the following refrigerants is most hazardous? a.R-113 b. R-11 c.R-717* d. R-152a 31. Which of the following is not a hydrocarbon refrigerant? a.Propane b. butane c.Isobutene d. inane* 32. A mixture of two or more refrigerants is called a ______ a.Zeotrope* b. desicant c.halocarbon d. absorbent 33. The society that sponsors research on refrigerants is called _______ a.ASHRAY b. ASHRAE* c.ASREA d. ARI 34. If Pi is the indicated horsepower and Pb is the indicated horsepower of a compressor, then what us mechanical efficiency, Em, equal to: a.Em = Pb/Pi b. Em = Pb-Pi

c.Em = Pi/Pb* d. Em = Pi-Pb 35. A household refrigerator that has a power input of 450 watts and a COP of 2.5 is to cool five large watermelons, 10 kg each, to 8 deg C. If the watermelons are initially at 20 deg C, determine how long will take for the refrigerator to cool them. The watermelons can be treated as water whose specific heat is 4.2 kJ/kg- oK. a.2120 seconds b. 2240 seconds * c.2230 seconds d. 2250 seconds 36. A thermoelectric refrigerator that resembles a small ice chest is powered by a car battery, and has a COP of 0.10. If the refrigerator cools a 0.350 L canned drink from 20 deg C to 40 deg C in 30 min, determine the average electric power consumed by the thermoelectric refrigerator. a.130 W * b. 100 W c.120 W d. 140 W 37. The refrigerant volume flow rate at the entrance of compressor were obtained from a test on a twin cylinder, single acting 15 cm x 20 cm, 320 rpm compressor ammonia refrigerating a plant to be 33 L/s. Determine the volumetric efficiency of the compressor. a.77.55% b. 97.6% c. 87.6% * d.65.65% 38.

The difference between dry-bulb and wet-bulb temperatures.

a.

Wet-bulb depression*

b.

Dry-bulb depression

c.

Cooling approach

d.

Cooling range

39.

The transmission of heat from one place to another by fluid circulation between spots of different temperature is called: a.

Convection*

b.

Radiation

c.

Conservation

d.

Conduction

40.

An enveloped area with significantly higher rate of heat transfer that the contiguous enclosure is called: a.

Air conditioned room*

b.

Thermal bridge

c.

Global irradiation

d.

Fenestration

41.

It is the return of radiation by a surface without change of frequency; the radiation is “bounced” off of the surface. a.

Reflection*

b.

Fenestration

c.

Transmission

d.

Absorption

42.

It is the passage of radiation through a medium without change of frequency.

a.

Transmission*

b.

Reflection

c.

Fenestration

d.

Absorption

43.

It is the rate at which energy must be removed from a space to maintain the temperature and humidity at the design values. a.

Heat gain

b.

Heat conduction

c.

Cooling load*

d.

Heating load

44.

A mode of heat transfer by electromagnetic waves, an entirely different phenomenon from conduction and convection; it can occur in a perfect vacuum and is usually impeded by an intervening medium. a.

Solar radiation

b.

Thermal conduction*

c.

Thermal radiation

d.

Thermal Convection

45.

It is the transport of energy by mixing in addition to conduction. It is associated with fluids in motion, generally through a pipe or duct or along a surface. a.

Thermal conduction

b.

Solar radiation

c.

Thermal convection*

d.

Heat transmission

46.

A method of air handling to an air conditioned room that produces more economical performance as compared with systems where reheat might be required is called:

a.

One hundred percent outdoor air

b.

Re-circulated air with external by-pass*

c.

Air washing system

d.

None of the above

47.

It is the temperature of a uniform environment at 0% relative humidity in which a person loses the same total amount of heat from the skin as in the actual environment. a.

Mean temperature

b.

Dry-bulb temperature

c.

Adiabatic equivalent temperature*

d.

Wet-bulb globe temperature

48.

It is the mechanism of heat transfer between parts of a continuum because of transfer of energy between particles or groups of particles at the atomic level. It is the mode of heat

transmission through the building structure, like the wall, due to the temperature difference between surfaces of the wall. a.

Heat transmission

b.

Thermal conduction*

c.

Solar radiation

d.

thermal convection

49.

A room contains air at 20C and 96 kPA at a relative humidity of 75%. Determine the enthalpy of moist air. a.

42.919 KJ/kgda

b.

46.515 KJ/kgda

c.

49.515 KJ/kgda*

d.

41.815 KJ/kgda

50.

An air-vapor mixture has a dry bulb temperature of 30 oC and a humidity ratio of 0.015 kg/kg d.a., calculate the enthalpy of the moist air. a.

68.527 kJ/kg d.a*

b.

86.627 kJ/kg d.a.

c.

65.817 kJ/kg d.a.

d.

67.628 kJ/kg d.a

51.

In an air conditioning system, if the re-circulated air is three times the outside air and the mass of supply air is 20 kg/s, what is the mass of the outside air? a. 4.9 kg/s

c. 5.1 kg/s*

b. 7 kg/s

d. 2.5 kg/s

52.

Five hundred kilograms of poultry enter a chiller at 8 oC and are frozen and chilled to a final temperature of -18 oC for storage in 15 hours. The specific heat above and below freezing are 3.18 kJ/kg oC and 1.55 kJ/kg oC respectively. The latent heat is 246 kJ/kg and the freezing temperature is -5 oC. Compute the product load. a.

5.45 kW

c. 6.35 kW

b.

2.85 kW*

d. 5.25 kW

53.

An ammonia simple saturation cycle operates with a suction pressure of 291.6 kPa and a condenser pressure of 1204 kPa develops 15 tons of refrigeration. Determine the theoretical horsepower of the compressor. The following enthalpies have been found at the condenser entrance = 1653 kJ/kg, exit = 346.6 kJ/kg, compressor entrance 1450.2 kJ/kg, exit = 1653 kJ/kg. a.

8.25 hp

c. 16 hp

b.

13 hp*

d. 25 hp

54.

A creamery must cool 20,000 liters of milk received each day from initial temperature 0f 29oC to a final temperature of 2 oC in 5 hours. If refrigeration losses amount to 10 percent of the cooling load, what must be the capacity of the refrigerating machine? Note: Specific heat of milk if 3.9 kJ/kg-K and S.G. = 1.05. a.

38.4 TOR*

c. 97.6 TOR

b.

56.5 TOR

d. 79.8 TOR

55.

A supply of 50 kg at 6 °C contained in a box is to be frozen to -18 °C in a freezer.

Determine the amount of heat that needs to be removed. The latent heat of the chicken is 247 kJ/kg, and its specific heat is 3.32 kJ/kg-C above freezing and 1.77 kJ/kg-C below freezing. The container box is 1.5 kg, and the specific heat of the box material is 1.4 kJ/kg-C. Also the freezing temperature of the chicken is -2.8 °C. a. 15,206.4 kJ*

c. 15,153.8 kJ

b. 53.5 kJ

d. 1,853.6 kJ

56.

A 50 MW power plant has an average load of 31,500kW and load factor of 70%. Find reserve over peak. a.

4 MW

b.

2 MW

c.

5 MW *

d.

6 MW

57.

The daily energy produced in a certain power plant is 480,000 kW-hrs. What is the daily average load? a.

10 MW

b.

14 MW

c.

25 MW

d.

20 MW *

58.

The annual energy produced in a 100 MW power plant is 438,000,000 kW-hrs. What is the annual capacity factor of the plant? a.

40 %

b.

50 %*

c.

35 %

d.

60 %

59.

A 75 MW power plant has an average load of 35000kW and load factor of 65%. Find reserve over peak. a.

21.15 MW *

b.

23.41 MW

c.

25.38MW

d.

18.76 MW

60.

A power plant is said to have/had a use factor of 48.5% and a capacity factor of 42.4%.

How many hours did it operate during the year? a.

6600.22 hrs

b.

7658.23 hrs *

c.

8300.32 hrs

d.

5659.23 hrs

61.

A fan described in a manufacturer’s table is rated to delivers 500 m^3/min at a static pressure (gage) of 254 cm of water when running at 250 rpm and requiring 3.6 kW. If the fan speed is changed to305 rpm and air handled were at 65 deg C instead of standard 21 deg C, find the power in kW. a.

3.85

b.

6.08

c.

4.66

d.

5.68*

62.

A double suction centrifugal pumps delivers 20 ft3/sec of water at a head of 12 m and running at 650 rpm. What is the specific speed of the pump? a.

5014.12 rpm

b.

6453.12 rpm

c.

2770.73 rpm*

d.

9967.73 rpm

63.

Determine the number of stages needed for a centrifugal pump if it is used to deliver 400 gal/min of water and pump power of 15 Hp. Each impeller develops a head of 30 ft. a.

6 b. 4 c. 5* d. 11

64.

The suction pressure of a pump reads 3 in. of mercury vacuum and discharge pressure reads 140 psi is use to deliver 120 gpm of water with specific volume of 0.0163 ft3/lb. Determine the pump work. a.

4.6 KW

b.

5.7 KW

c.

7.4 KW*

d.

8.4 KW

65.

A submersible pump delivers 350 gpm of water to a height of 5 ft from the ground. The pump was installed 150 ft below the ground level and draw down of 8 ft during the operation. If water level is 25 ft above the pump, determine the pump power. a.

7.13 KW

b.

4.85 KW

c.

7.24 KW

d.

9.27 KW*

66.

The initial condition of air in an air compressor is 98 KPa and 27C and discharge air at 450 KPa. The bore and stroke are 355 mm and 381 mm, respectively with percent cleared of 8% running at 300 rpm. Find the volume of air at suction. a.

541.62 m3/hr

b.

550.62 m3/hr

c.

561.62 m3/hr

d.

571.62 m3/hr*

67.

An air compressor has a suction volume of 0.35 m3/sec t 97 KPa and discharges to 650 KPa. How much power saved by the compressor of there are two stages? a.

18.27 KW

b.

16.54 KW

c.

13.86 KW

d.

11.58 KW*

68.

A two stage air compressor has an intercooler pressure of 4 kg/cm2. What is the discharge pressure if suction pressure is 1 kg/cm2? a.

2 kg/cm2

b.

8 kg/cm2

c.

13 kg/cm2

d.

16 kg/cm2 *

69.

A two stage air compressor compresses air at 100 KPa and 22C discharges to 750 KPa. If intercooler intake is 105C. Determine the value of n. a.

1.500

b.

1.325*

c.

1.355

d.

1.388

70.

A single acting compressor has a volumetric efficiency of 89%, operates at 500 rpm. It takes in air at 900 KPa and 30C and discharges it at 600 KPa. The air handled is 8 m3/min measured at discharge condition. If compression is isentropic, find mean effective pressure in KPa. a.

233.34*

b.

973.16

c.

198.24

d.

204.82

71.

Determine the mass of water vapour contained in a 150m3 room at 100 kPa, 23C and 40% relative humidity. From steam tables: Psat @ 23C=2.810 kPA. a.

1.6242 kg

b.

1.9342 kg

c.

1.2342 kg*

d.

2.2342 kg

72.

The gas density of chimney is 0.75 kg/m^3 and air density of 1.15 kg/m^3. If the driving pressure is 0.25 kPa, determine the height of the chimney. a.

54.6 m

b.

63.7 m *

c.

74.6 m

d.

68.5 m

73.

The actual velocity of gas entering in a chimney is 8 m/sec. The gas temperature is 25 deg C and pressure of 98 kPa with a gas constant of 0.287 kJ/kg-K. Determine the chimney diameter if mass of gas is 50,000 kg/hr. a.

1.56 m

b.

1.81 m

c.

3.56 m

d.

1.39 m*

74.

A coal fired steam boiler uses 3000 kg of coal per hour. Air required for combustion is 15.5 kg per kg of coal at barometric pressure of 98.2 kPa. The flue gas has temperature of 285 deg C and an average molecular weight of 30. Assuming an ash loss of 11% and allowable gas velocity of 7.5 m/sec, find the diameter of chimney. a.

1.91 m *

b.

1.81 m

c.

2.62 m

d.

2.93 m

75.

A power plant situated at an altitude having an ambient air of 96.53 kPa and 23.88 deg C. Flue gases at a rate of 5.0 kg/sec enter the stack at 200 deg C and leaves at 160 deg C. The flue gases gravimetric analysis are 18% CO2, 7% O2 and 75% N2. Calculate the diameter of stack in meters for driving pressure of 0.20 kPa. a.

0.76

b.

0.85

c.

0.95*

d.

1.15

76.

The compression ratio of an OTTO cycle is 9. If the initial pressure is 150 kPa, determine the final pressure. a.

1250.10 kPa

b. 4251.10 kPa

c. 2251.10 kPa

d. 3251.10 kPa*

77.

In an air standard Diesel cycle, compression starts at 100 kPa and 300 K. The compression ratio is 16 to 1. The maximum cycle temperature is 2031 K. Determine the thermal efficiency. a.

61.27%

b. 60.27%*

c. 63.27%

d. 65.27%

78.

There are supplied 400 kJ per cycle to an ideal Diesel engine operating on 500 g air, P1=100 kPa, t1=50C. At the end of compression, P2=4000 kPa. Determine the effective pressure of the engine. a.

657.57 kPa

b. 457.57 kPa

c. 557.57 kPa*

d. 358.57 kPa

79.

A superheat steam Rankine cycle has a turbine inlet conditions of 17.5 MPa and 530C expands in a turbine to 0.007 MPa. The turbine and pump polytropic efficiencies are 0.9 and 0.7 respectively. Pressure losses between pump and turbine inlet are 1.5 MPa. What should be the pump work in kJ/kg? a.

29.87 kJ/kg

b. 32.47 kJ/kg

c. 27.13 kJ/kg*

d. 32.25 kJ/kg

80.

Steam enters a turbine 80 lbs of steam per minute with an enthalpy of 1700 Btu/lb and velocity of 98 ft/s. it leaves the turbine at 1400 Btu/lb and 880 ft/s. The heat loss is 90,000 Btu/hr. find the horse power output of the turbine. a.

301.56 hp

b. 482.45 Hp

c. 501.62 hp*

d. 601.62 hp

81.

Pump at its best efficiency point (BEP) has a capacity of 12,500 gpm while developing a head of 60ft at a rotative speed of 1450 rpm. What is the specific speed of the pump? a.

2760

b. 1460

c. 7520*

d. 6892

82.

A 30Hp pump delivers 475 gpm of gasoline (y = 42.5 lb/ft3) at 20C with 78% efficiency.

What pressure rise result across the pump? a.

30.3 psi

b. 84.5 psi*

c. 120.3 psi

d. 73.2 psi

83.

A piston positive-displacement pump (PDP) has 8-in diameter and a 2.5-in stroke. Its crankshaft rotates at 300 rpm. Calculate its output at 94 percent volumetric efficiency.

a.

12.26 cfm

b. 20.51 cfm*

c. 10 cfm

d. 11.50 cfm

84.

A centrifugal pump (efficiency 86%) lifts water through a total height of 42 m from reservoir to discharge. Pumping is through 300m of 75mm diameter pipe at the rate of 20 liter/sec.

If the pipe friction factor, f = 0.025, what kW is required? a.

28.4 kW

b. 33.4 kW

c. 26 kW

d. 9 kW*

85. A pump produces a head of 10 m. The volumetric flow rate through the pump is 6.3 x 10-4 m3/s. The fluid pumped is oil with a specific gravity of 0.83. Approximately how much energy does the pump consume in one hour?

a. 8.6 kJ

b.17 kJ

c. 180 kJ *

d. 200 kJ

86.

It is desired to double the COP of a reversed Carnot engine for cooling from 5.0 by raising the temperature of the heat addition while keeping the temperature of the heat rejection constant.

By what percentage must the temperature of heat addition be raised? a.

10% b. 9.1%* c. 8.1% d. 7.2%

87.

In order to cool 1 ton (100kg) of water at 20oC in an insulated tank, a person pours 80 kg of ice at -5oC into the water. Determine the final equilibrium temperature in the tank. The melting temperature and the hat of fusion of ice at atmospheric pressure are 0oC and 333.7 kJ/kg, respectively. a.

12.43oC*

b.

13.43oC

c.

15.43oC

d.

17.43oC

88.

A thermoelectric refrigerator that resembles a small ice chest is powered by a car battery, and has a COP of 0.10. If the refrigerator cools at 0.350L canned drink from 20OC to 4OC in 30 min. determine the average electric power consumed by the thermoelectric refrigerator. a.

130 watts*

b.

100 watts

c.

120 watts

d.

140 watts

89.

A refrigeration system is to cool bread loaves with an average mass of 450 g from 22OC to -10OC at a rate of 500 loaves per hour by refrigerated air. Taking the average specific and latent heats of bread to be 2.93 kJ/kg, OC and 109.3 kJ/kg, respectively, determine the product load. a.

540.7 kJ/min

b.

350.6 kJ/min

c.

761.5 kJ/min*

d.

409.9 kJ/min

90. A batch of concrete consisted of 200 lbs fine aggregate, 350 lbs coarse aggregate, 94 lbs cement and 5 gallons water. The specific gravity of the sand and gravel may be taken as 2.65 and that of the cement as 3.10. What was the weight of concrete in place per cubic foot? a. 153.58 lb/ft3 * b.145.58 lb/ft3 c. 161.58 lb/ft3 d. 140.68 lb/ft3 91. Horizontal stream with water with a cross sectional area of 0.1 ft2 and a velocity 40 ft/s has kinetic energy in ft.lbf/sec nearest to: a.

2,500

b.

6,200*

c.

11,700

d.

56,000

92. Water is flowing in a pipe with a radius of 10” at a velocity of 5m/s. at the temperature in the pipe, the density and viscosity of the water are as follows: P=997.9 kg/m3; U=1.131 pa.s. What is the Reynold’s number for this situation? a.

44.0

b.

88.2

c.

1140

d.

2241*

93. The Reynolds number of a sphere falling in air is 1x10^6. If the sphere’s radius is 1ft, what is its velocity? (P air=0.00234 slug/ft3, U air=3.8x10lbf-sec/ft3) a.

2.5 ft/sec*

b.

5.1 ft/sec

c.

40.6 ft/sec

d.

80.2 ft/sec

94. The flow rate of water through a cast iron is 5000 gallons per mnute. The diameter of the pipe is 1 foot, and the coefficient of friction is f=0.0173. What is the pressure drop over a 100 foot length of pipe? a.

21.078 lbf/ft2

b.

23.78 lbf/ft2

c.

334.26 lbf/in2

d.

337.26 lbf/ft2*

95.

A diesel cycle has a cut off ratio of 2.5 and expansion ratio of 4. Find the clearance of the cycle. a.

9.11 %

b.

5.55 %

c.

11.11 %*

d.

15.16 %

96.

Air flows through a nozzle with temperature of entrance of 420 ˚ K stagnation temperature of 468 ˚ K. Find the mach number. a.

0.744

b.

0.754*

c.

0.746

d.

0.764

97.

Air enters a diffuser with a velocity of 200m/s. Determine the velocity of sound if air temperature is 30 ˚ C.

a.

349 m/s*

b.

359 m/s

c.

368 m/s

d.

379 m/s

98.

At standard atmospheric conditions, what is the approximate speed of sound?

a.

336 m/s*

b.

360 m/s

c.

632 m/s

d.

346 m/s

99.

Air pass thru a nozzle with efficiency of 90%. The velocity of air at the exit is 600 m/s.

Find the actual velocity at the exit. a.

383 m/s

b.

541 m/s

c.

459 m/s

d.

568 m/s*

100. Air enters a nozzle steadily at 2.21 kg/m3 and 30 m/s. what is the mass flow rate through the nozzle if the inlet area of the nozzle is 80 cm2. a.

0.30 kg/s

b.

2.5 kg/s

c.

5.2 kg/s

d.

0.53 kg/s* 11. A form of thermal convection when the bulk of the fluid is moving relative to the heat transfer surface because such motion is usually caused by a blower, fan, or pump that is forcing the flow. a. Slow convection b. Forced convection* c. Thermal convection d. Free convection 12. Water is boiler in a pan on a stove at sea level. During 10 minutes of boiling, it is observed that 500 grams of water has evaporated. Then the rate of heat transfer to the water is: A. 152.84 KJ/min B. 112.85 KJ/min *

C. 91.8 KJ/min D. 134.5 KJ/min 13. For heat transfer purposes, a standing man can be modeled as a 30 cm diameter, 170 cm long vertical cylinder with both the top and bottom surfaces insulated and with the side surface at an average temperature of 34oC. For a convection heat transfer coefficient of 15 W/m2- oC, determine the rate of heat loss from this man by convection in an environment at 20oC. A. 336.46 watts* B. 346.46 watts C. 356.46 watts D. 366.46 watts 14. A 15 cm thick wall has a thermal conductivity of 5W /m-°K. If inside and outside surface temperature of the wall are 200°C and 20°C, respectively. Determine the heat transmitted.

A. 5.67 KW/m2* B. 4.68 KW/m2 C. 8.87 KW/m2 D. 6.87 KW/m2 15. Two walls of cold storage plant are composed of an insulating material (l = 0.25 KJ/hrm-°C), 100 mm thick at the outer layer and material (l = 3.5 KJ/hr-m-°C), 15 cm thick at inner layer. If the surface temperature at cold side is 30°C and hot side is 250°C, find the heat transmitted per square meter.

A. 0.138 KW/m2* B. 0.450 KW/m2 C. 0.025 KW/m2 D. 0.065 KW/m2 COMBUSTION 16. In compression-engine, the combustion of air-fuel mixture is self-fuel ignited as a result of compressing the mixture above its a. self-developed temperature b. mixing temperature c. self-feed temperature d. self-ignition temperature * 17. The fuel used in a power plant that is used during peak periods. a. Liquid* b. Solid c. Gas d. Atomic 18. An engine-generator rated 9000 KVA at 80% power factor, 3 phase, 4160 V has an efficiency of 90%. If overall plant efficiency is 28%, what is the heat generated by the fuel.

A. 18,800 KW B. 28,800 KW C. 7500 KW D. 25,714 KW *

19. A 305 mm x 457 mm four stroke single acting diesel engine is rated at 150 KW at 260 rpm. Fuel consumption at rated load is 0.56 kg/KW-hr with a heating value of 43,912 KJ/kg. Calculate brake thermal efficiency A. 10.53% B. 27.45% C. 14.64% * D. 18.23% 20. The ultimate analysis of coal is given below: C = 68.5% , H= 2.5%, S = 1.5%, O = 3.5%, Ash=12.0%. Calculate the nearest higher heating value of coal. a. 23,400 KJ/kg b. 17,500 KJ/kg c. 26,300 KJ/kg* d. 35,500 KJ/kg FLUID MECHANICS 21. At any point in fluid at rest the pressure is the same in all directions. This principle is known as: a. Bernoulli principle b. Archimedes principle c. Pascal’s law* d. Torrecelli’s law 22. Two tubes are mounted to the roof of a car. One tube points to the front of the car while the other point to the rear. The tubes are connected to a manometer filled with fluid of specific gravity. 0.60. When the height difference is 2 inches, what is the car’s speed?

A. 46 mph B. 43.8 mph C. 50 mph* D. 62 mph 23. What is the density of a stone that weighs 19.9 lb (88 N) in air and 12.4 lb (55 N) in water?

A. 2,651.2 kg/m3* B. 2,612.5 kg/m3 C. 2,578.2 kg/m3 D. 26,700 kg/m3 24. Pressure drop across a turbine is 30 psi, the flow rate is 60 gpm. Calculate the power output of the turbine.

A. 0.41 hp B. 1.05 hp* C. 6.30 hp D. 2.54 hp 25. The fluid in a manometer tube is 60% water and 40% alcohol (SG = 0.8). What is the manometer fluid height difference if a 6.2 psi pressure is applied across the row ends of a manometer?

A. 15.5 in B. 186 in C. 36 in D. 215 in*

REFRIGERATION AND AIRCONDITIONING 26. The total heat of the air is the function of: a. WB Temperature* b. DB Temperature c. DP Temperature d. WB Depression 27. Which of the following is NOT a type of water cooled condenser: a. Double pipe c. Double shell* b. Shell and coil d. Shell and tube 28. Component of absorption refrigeration sytem in which the solution is cooled condenser in refrigeration? a. Rectifier b. Evaporator c. Generator d. Absorber* 29. A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13 Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the refrigerating effect. a 52.25 Btu/lb b 54.48 Btu/lb* c 56.68 Btu/lb d 58.89 Btu/lb 30. A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13 Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the rate of Freon-12 circulated. a 181.7 lb/min b 183.6 lb/min* c 185.3 lb/min d 187.9 lb/min 31. A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13 Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the net work required per pound of Freon-12 circulated. a 10.09 Btu/lb b 11.09 Btu/lb * c 12.09 Btu/lb d 13.09 Btu/lb 32. A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13 Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the coefficient of performance. a 3.91 b 4.91* c 5.91

d 6.91 33. An ammonia simple saturation cycle operates with a suction pressure of 291.6 kPa and a condenser pressure of 1204 kPa develops 15 tons of refrigeration. Determine the theoretical horsepower of the compressor. The following enthalpies have been found at the condenser entrance = 1653 kJ/kg, exit = 346.6 kJ/kg, compressor entrance 1450.2 kJ/kg, exit = 1653 kJ/kg. a. 8.25 hp b. 25.2 hp c. 13.0 hp* d. 18.8 hp 34. Consider a refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigeration has a COP of 1.3 and the cost of electricity is 6 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed. a. P31.30 b. P33.85 c. P35.19 d. P37.20* 35. A reversed Carnot cycle has a refrigerating COP of 1.5. Determine the ratio TH/TL? A.1.667* B.1.252 C.1.501 D.1.333 36. A household refrigerator with EER 8.0 removes heat from the refrigerated space at a rate of 90 kJ/min. Determine the rate of heat transfer to the kitchen air.

A.69.65 kJ/min B.148.35 kJ/min C.80.46 kJ/min D.128.46 kJ/min* 37. The power requirement of a Carnot refrigerator in maintaining a low temperature region at 300 K is 2.8 kW per ton. Find the heat rejected. a. 5.02 kW b. 7.12 kW c. 6.32 kW* d. 4.44 kW 38. Fish weighing 11,000 kg with a temperature of 20C is brought to a cold storage and which shall be cooled to -10C in 11 hours. Find the required plant refrigerating capacity in tons of refrigeration if the specific heat of fish is 0.7 kCal/kg -C above freezing and 0.30 kCal/kg -C below freezing point which is -3C. The latent heat of freezing is 55.5 kCal/kg. a. 24.38 TOR* b. 19.69 TOR c. 14.48 TOR d. 26.48 TOR 39. A refrigeration system is used to cooled water in the evaporator a 8 kg/s of water from 30C to 2C. Find the tons of performance required. a. 136.75 TOR b. 139.45 TOR

c. 121.35 TOR d. 266.75 TOR* 40. A two stage cascade vapor compression refrigeration system uses ammonia in the lowtemperature loop and R-12 in the high-temperature loop. The ammonia provides 15 tons cooling. If the high- loop temperature requires 10.12 kW compressor power and lowloop 15.93 kW, determine the COP of the system. a. 5.032 TR b. 7.458 TR c. 4.422 TR d. 2.027 TR* 41. The mass of an outside air at 50°C in an air conditioning unit is 60 kg. Find the temperature after mixing with 40 kg with recirculated air at 35°C. a. 35°C b. 44°C* c. 59°C d. 33°C 42. Find the sensible heat factor of an air-conditioning unit having a sensible heat load of 90 kW and latent heat load of 40 kW. a 65.50% b 67.35% c 69.23%* d 71.45% 43. Re-circulated air of 8 kg/s with 53 KJ/kg dry air enthalpy and outside air of 2 kg/s with 90KJ/kg dry air enthalpy enters the conditioning unit. Determine the air conditioning capacity of air conditioning apparatus if the supply enthalpy to conditioned space is 42 kJ/kg dry air. a. 154 KW b. 164 KW c. 174 KW d. 184 KW* 44. Fifty kilogram of cooling tower per second enters the condenser 15˚C and leaves at 50˚C. Find the heat carried away by water. a. 2234.45 kW b. 7327.25 kW* c. 5340.65 kW d. 4140.25 kW 45. Copra enters a dryer containing 60% water and 40% of solids and leaves with 5% water and 95% solids. Find the weight of water removed based on each pound of original product. a. 0.48 lb b. 0.47 lb c. 0.58 lb* d. 0.57 lb 46. Wet material, containing 220% moisture (dry basis) is to be dried at the rate of 1.5 kg/s in a continuous dryer to give a product containing 10% moisture (dry basis). Find the moisture removed. a. 3513.75 kg/hr b. 3543.75 kg/hr*

c. 3593.55 kg/hr d. 3643.55 kg/hr 47. The enthalpy at the entrance of the condenser is 1660 KJ/kg and exit is 315 KJ/kg. The compressor has an enthalpy of 1450 KJ/kg at entrance. Determine the COP. A. 4.2 B. 2.0 C. 5.4* D. 6.0 48. The refrigerating effect of 100 tons refrigeration is 117 KJ/kg. Determine the mass flow of refrigerant.

A. 1kg/sec B. 2kg/sec C. 3 kg/sec* D. 4 kg/sec 49. Fifty gallons per minute of water enters a cooling tower at 115°F. Atmospheric air at 60°F and 55% relative humidity enters the tower at 6,000 cfm and leaves at 90°F saturated. Determine the exit temperature of water, °F A. 56.33 B. 65.33 C. 76.61* D. 45.34 50. The change of enthalpy in a heating chamber of dryer is 25 Btu and the mass of air supplied is 30,000 lb/hr. What is the heat supplied by heater?

A. 560 KW B. 450 KW C. 350 KW D. 220 KW*

INDUSTRIAL PLANT ENGINEERING 51. The number of nozzles will depend on the quantity of steam required by the turbine. If nozzle occupy the entire arc of the ring, the turbine is said to have A. Partially full peripheral admission B. One-half full peripheral admission C. Maximum peripheral admission D. Full peripheral admission* 52. The quantity of refrigerant stored at some point is the refrigeration system for operational, service, or standby purposes A. Pressure vessel B. Pumpdown charge* C. Liquid receiver D. Accumulator 53. Needs only single pump regardless of number of heaters A. Open heater B. Closed heater* C. Mono heater D. Regenerative heater

54. A 2 KW centrifugal compressor operates with suction conditions of 100 Kpa absolute and 25C. The pressure ratio for the unit is 3 and isentropic compression efficiency is 70%. Determine the discharge pressure. a 300 kPa abs* b 400 kPa abs c 250 kPa abs d 150 kPa abs 55. A 2 KW centrifugal compressor operates with suction conditions of 100 Kpa absolute and 25C. The pressure ratio for the unit is 3 and isentropic compression efficiency is 70%. Determine the discharge temperature (actual). a 333 K b 498 K c 455 K* d 587 K 56. A 2 KW centrifugal compressor operates with suction conditions of 100 Kpa absolute and 25C. The pressure ratio for the unit is 3 and isentropic compression efficiency is 70%. Determine the work input per kg of air. a (-)157.8 KJ/kg* b (-)149.9 KJ/kg c (-)153.2 KJ/kg d (-)164.6 KJ/kg 57. A centrifugal air compressor has a a pressure ratio of 3 and inlet conditions of 27 C and103 kPa abs. The mass flow rate is 5kg/sec measured at inlet. For isentropic compression, find the discharge temperature. a 378.9 K b 410.6 K * c 452.2 K d 524.7 K 58. A centrifugal air compressor has a a pressure ratio of 3 and inlet conditions of 27 C and103 kPa abs. The mass flow rate is 5kg/sec measured at inlet. For isentropic compression, find the discharge pressure. a 103 kPa b 239 kPa c 432 kPa d 309 kPa* 59. A centrifugal air compressor has a a pressure ratio of 3 and inlet conditions of 27 C and103 kPa abs. The mass flow rate is 5kg/sec measured at inlet. For isentropic compression, find the required internal power. a 447 KW b 333 KW c 555 KW * d 595 KW 60. A double suction centrifugal pumps delivers 20 ft3/sec of water at a head of 12 m and running at 650 rpm. What is the specific speed of the pump?

A. 2770.72 rpm * B. 9255.16 rpm C. 5370.89 rpm D. 3883.69 rpm

61. Determine the number of stages needed for a centrifugal pump if it is used to deliver 400 gal/min of water and pump power of 15 Hp. Each impeller develops a head of 50 ft.

A. 3* B. 4 C. 5 D. 6 62. The suction pressure of a pump reads 3 in. of mercury vacuum and discharge pressure reads 140 psi is use to deliver 120 gpm of water with specific volume of 0.0163 ft3/lb.

Determine the pump work.

A. 7.39 KW * B. 9.75 KW C. 10.47 KW D. 8.48 KW 63. A submersible pump delivers 350 gpm of water to a height of 5 ft from the ground. The pump were installed 150 ft below the ground level and draw down of 8 ft during the operation. If water level is 25 ft above the pump, determine the pump power.

A. 10.32 KW B. 9.271 KW* C. 8.65 KW D. 4.39 KW 64. A simple Rankine cycle produces 40 MW of power, 50 MW of process heated and rejects 50 MW of heat to the surroundings. What is the utilization factor of this cogeneration cycle neglecting the pump work?

A. 64% * B. 55% C. 69% D. 75% 65. A steam generator with economizer and air heater has an overall draft loss of 25.78 cm of water. If the stack gases are at 177C and if the atmosphere is at 101.3 Kpa and 26C, what theoretical height of stack in meters is needed when no draft fan are used? Assume that the gas constant for the flue gases is the same as that for air.

A. 651.10 * B. 633.59 C. 785.33 D. 697.78 66. A fan pressure of 2.54 cm of water at 1.42 m3 per second of air at static pressure of 2.54 cm of water through a duct 300 mm diameter and discharges it through a duct 275 mm diameter. Determine the static fan efficiency if total fan mechanical is 75% and air measured at 25 and 60 mm Hg. A. 53.69% * B. 48.32% C. 59.44% D. 62.13% 67. A fan is powered by a 0.5 hp motor and delivers air at a rate of 85 m3/min. Determine the highest value for the average velocity of air mobilized by the fan. The density of air is 1.18 kg/m3.

A. 24.27 m/s B. 29.66 m/s

C. 18.99 m/s D. 21.13 m/s* 68. A pump delivers 1000 gallons per minute of water at 30 ft elevation. The suction pressure is 5 psi and discharge pressure is 20 psi. Find the power rating of motor to be use if pump efficiency is 75%. a 81.23 hp b 21.78 hp* c 34.23 hp d 43.23 hp 69. A pump has a head of 30m at 500 rpm. What is the increase in head developed by the pump is speed increased to 1200 rpm? a 142.8 m* b 132.3 m c 153.4 m d 186.4 m 70. A reciprocating pump has 350 mm x 400 mm cylinder running at 360 rpm. If percent slip is 12%, find the volumetric efficiency of the pump. a 82% b 84% c 86% d 88%* 71. A three stages air compressor compresses air from 100 kpa to 1000 kpa. Find the intercooler pressure between the first and second stage.

A. 662.75 kpa B. 215.44 kpa* C. 477.88 kpa D. 325.55 kpa 72. The discharge pressure of an air compressor is 5 times the suction pressure. If volume flow at suction is 0.1 m3/sec, what is the suction pressure if compressor work is 19.57 kw? (use n=1.35) A. 107 kpa B. 93 kpa C. 102 kpa D. 98 kpa* 73. An air compressor has a suction volume of 0.35 m3/sec at 97 KPa and discharges to 650 KPa. How much power saved by the compressor of there are two stages?

A. 15.33 KW B. 11.58 KW* C. 17.69 KW D. 23.44 KW 74. A two stage air compressor has an intercooler pressure of 4 kg/cm2. What is the discharge pressure if suction pressure is 1 kg/cm2?

A. 8 kg/cm2 B. 16 kg/cm2* C. 24 kg/cm2 D. 12 kg/cm2 75. Water from a reservoir A 10 m elevation is drawn by a motor driven pump to an upper reservoir B at 72m elevation. Suction and discharge head loss are 0.15m, respectively.

For discharge rate of 15li/sec, find the power input to the motor if overall efficiency is 65%.

A. 12.65 KW B. 23.54 KW C. 14.17 KW* D. 45.35 KW

POWER PLANT ENGINEERING 76. At the beginning of the compression stroke an ideal Otto cycle has an air pressure of 15 psia, a temperature of 75F and a specific volume of 13.2 cubic feet per pound. At the end of compression the specific volume is 1.76 cubic feet per pound. The heat supplied to the cycle is 325 Btu/lb. Calculate the highest temperature of the cycle. a 3246 R* b 3346 R c 3478 R d 3198 R 77. One pound of air at 100F is mixed with another pound of air at 40F. The mixing process is constant pressure with constant specific heat. Calculate the change of entropy for the lb of gas originally at 100F. a -0.01121 b -0.01321* c -0.02425 d -0.03525 78. One pound of a certain working substance receives 100 Btu of heat at a constant temperature of 2000R. Calculate the available energy with respect to a 100F receiver. a 68 Btu/lb b 72 Btu/lb* c 76 Btu/lb d 80 Btu/lb 79. An Otto Cycle, with a 7 to 1 compression ratio, has 320 Btu/lb of heat supply. At the beginning of the compression process the pressure and temperature are 14.7 psia and 60F. Assuming constant specific heat, calculate the peak pressure. a 582 psi b 595 psi* c 603 psi d 614 psi 80. A Diesel cycle has a 16 to 1 compression ratio and a peak cycle temperature of 2912R. Conditions at the beginning of compression are 14.7 psia and 60F. Assuming constant specific heat determine the heat supplied. a 280 Btu/lb b 300 Btu/lb c 320 Btu/lb* d 340 Btu/lb 81. A Brayton cycle with a pressure ratio of 6 has compressor inlet conditions of 70F and 14.7 psia. The turbine inlet temperature is equal to 1500F. Calculate the isentropic turbine discharge temperature.

a 1089.8 R b 1174.7 R* c 1235.5 R d 1325.3 R 82. A Rankine steam power cycle operates with steam at 600 psia and 850F from the boiler and a condenser pressure of 1 inch of mercury absolute. Enthalpies are h4=49.4Btu/lb, h1=1435.4 Btu/lb, s1=s2=1.6559 Btu/lb-R, h2=890.0Btu/lb, h3=47.1 Btu/lb, s4=s3=0.09146 Btu/lb-R. Determine the heat supplied. a 1286 Btu/lb b 842.9 Btu/lb c 1386 Btu/lb* d 543.1 Btu/lb 83. In an air standard brayton cycle, the compressor receives air at 101.325 kPa, 21C and it leaves at 600kPa at the rate of 4kg/s. Det the turbine work if the temperature of the air entering the turbine is 1000C. a. 3088 kW b. 2182 kW c. 3128 kW d. 2028 kW* 84. A turbine has a mechanical efficiency of 93%, volumetric efficiency of 95% and total efficiency of 82%. If effective head is 45 m, find the total head.

A. 32.73 m B. 45.89 m C. 41.76 m* D. 35.88 m 85. A heat engine receives hat from a source at 1200oK at a rate of 5000KJ/s and rejects the waste heat to a medium at 3000oK. The power output of the heat engine is 180 KW. Determine the irreversible rate for this process.

A. 185 KW B. 205 KW C. 215 KW D. 195 KW* 86. In a Rankine cycle steam enters the turbine at 2.5 Mpa (enthalpies & entropies given) and condenser of 50 Kpa (properties given), what is the thermal efficiency of the cycle.

At 2.5 Mpa: hg = 2803.1 KJ/kg sg = 6.2575 At 50 kpa: sf = 1.0910 sfg = 6.5029 hf = 340.49 hfg = 2305.4 vf = 0.0010300 A. 14.33% B. 47.39% C. 33.23% D. 25.55%* 87. A thermal power plant generates 5 MW has also 300 KW power needed for auxiliaries.

If the heat generated by fuel is 13,000 KJ/sec, determine the net thermal efficiency.

A. 35.78% B. 36.15%* C. 30.56%

D. 33.67 88. A water tube boiler has a heating surface area of 500 m2. For a developed boiler hp of 825. Determine the percent rating of the boiler.

A. 120.15% B. 160.15% C. 150.15%* D. 300.15% 89. A steam engine has 10% brake thermal efficiency and delivers 750 kg/hr steam. The enthalpy of engine entrance is 2800 KJ/kg and condenser exit is 450 KJ/kg. Determine the brake power of the engine. Answer C A. 46 KW B. 47 KW C. 49 KW* D. 48 KW 90. What is the required base area of the foundation to support an engine with specified speed of 1200 rpm and weight of 9,000 kg? Assume bearing capacity of soil as 47.867 kpa. Use e = 0.11 A. 5.57 m2* B. 8.87 m2 C. 7.75 m2 D. 10.5 m2 91. A high discharge type turbine. a. Impulse turbine b. Propeller turbine * c. Francis turbine d. Deriaz turbine 92. Use to minimize the speed rise due to a sudden load rejection. a. Needle valve b. Shut-off valve c. Wicket gate d. Jet deflector* 93. Is the speed of the turbine when the head on the turbine is one meter? a. Specific speed b. Utilized speed c. Rated speed d. Unit speed* 94. Presently the highest steam temperature allowed at the turbine inlet is about: a. 340 C b. 520 C c. 620 C* d. 1020 C 95. A 2000 KW diesel engine unit uses 1bbl oil per 525 KWH produced. Oil is 25API. Efficiency of generator 93%, mechanical efficiency of engine 80%. What is the thermal efficiency of the engine based on indicated power?

A. 31.69 B. 29.47 C. 39.60* D. 35.60

96. In a hydro-electric plant the brake power is 1800 KW running at 450 rpm and net head of 30 m. Determine the specific speed of the turbine.

A. 60.29 rpm B. 65.29 rpm C. 75.29 rpm D. 71.29 rpm* 97. In Francis turbine, the pressure gage leading to the turbine casing reads 380 Kpa. The velocity of water entering the turbine is 8 m/sec, if net head of the turbine is 44 m, find the distance from center of spiral casing to the tailrace.

A. 2.0 m* B. 1.5 m C. 3.0 m D. 5.5 m 98. The annual energy produced in a 100 MW power plant is 438,000,000 KW – hrs. What is the annual capacity factor of the plant?

A. 40% B. 50%* C. 35% D. 60% 99. A thermal power plant generates 5 MW has also 300 KW power needed for auxiliaries.

If the heat generated by fuel is 13,000 KJ/sec, determine the net thermal efficiency.

A. 35.78% B. 36.15%* C. 30.56% D. 33.67 100. The rated boiler horsepower of a fire tube boiler is 500 Hp. What is the heating surface area of the boiler?

A. 500 m2 B. 300 m2 C. 400 m2 D. 550 m2* 12. What is the log mean temperature difference in C of a double-pipe counterflow heat exchanger where a fluid enters at 90C and exits at 50C. inside the inner pipe another fluid enters at 20C and exits at 60C. a

0

b

30*

c

75

d

35

13. Sea water for cooling enters a condenser at 25C and leaves at 40C. The condenser temperature is 45C, what is the log mean temperature difference? a

16.34C

b

10.82C*

c

23.34

d

12.34

14. A counterflow heat exchanger is designed to heat fuel oil from 45C to 100C while heating fluid enters at 150C and leaves at 115C. Calculate the arithmetic mean temperature difference. a

40C

b

50C

c

60C*

d

70C

15. Water is boiling in a pan on a stove at sea level. During 10 minutes of boiling, it is observed that 200 grams of water has evaporated. Then the rate of heat transfer to the water is: a. 0.85 KJ/min b. 45.1 KJ/min* c. 41.8 KJ/min d. 53.5 KJ/min 16. For a heat transfer purposes, a standing man can be modeled as a 30 cm diameter, 170 cm long vertical cylinder with both the top and bottom surfaces insulated and with the side surface at an average temperature of 34 deg. C. for convection heat transfer coefficient of 15 W/m^2-C, determine the rate of heat loss from this man by convection in an environment at 20 deg. C. a. 315.46 watts b. 326.46 watts c. 336.46 watts* d. 346.46 watts Combustion Engineering 17. Which Hydrocarbon has a chemical formula of C2H5OH? a Ethanol* b Methane c Octane d Ehtane 18. Which Hydrocarbon has a chemical formula of C8H18? a. Ethanol b. Methane c. Octane* d. Ehtane 19. Which Hydrocarbon has a chemical formula of CH4?

a. Ethanol b. Methane* c. Octane d. Ehtane 20. Which Hydrocarbon has a chemical formula of C2H6? a. Ethanol b. Ethane* c. Octane d. Methanol 21. For something to burn, you need fuel and air. Which part of air is needed to sustain a fire? a. Nitrogen b. Phlogiston c. Carbon Dioxide d. Oxygen*

Fluid Mechanics 21. The pressure drop across a turbine is 200 kPa. The flow rate is 0.25 m3/min. What is most nearly the power output of the turbine? a. 0.42 kW b. 0.83 kW* c. 0.95 kW d. 1.3 kW

22. Water is pumped at 1m3/s to an elevation of 5 m through a flexible hose using a 100% efficient pump rated at 100 kW. Using the same length of hose, what size motor is needed to pump 1m3/s of water to a tank with no elevation gain? Both ends of the hose are at atmospheric pressure. Neglect kinetic energy effects. a. 18 kW b. 21 kW c. 38 kW d. 51 kW* 23. Calculate the Reynolds number for water at 20° C flowing in an open channel. The water is flowing at a volumetric rate of 0.8 m 3js. The channel has a height of 1.2 m and a width of 2.5 m. At this temperature, water has a kinematic viscosity of 1.02 x 106 m 2 js. a. 6.5 X 105 * b. 7.5 x 105 c. 8.2 x 105 d. 2.2 x 106

24. The Reynolds number of a sphere falling in air is 1 x 106 • If the sphere's radius is 0.5 m, what is most nearly its velocity? (Pair = 1.225 kg/m 3, air = 1.789 x 10-5 Pa·s) a. 2.5 m/s b. 5.2 m/s c. 12 m/s d. 15 m/s*

25. A circular cylinder 4 m long and 3 m in diameter is in an air stream. The flow velocity is 5 m/s perpendicular to the longitudinal axis of the cylinder. Given that the coefficient of drag on the cylinder is 1.3, and the density of air is 1.225 kg/m3 , what is most nearly the drag force on the cylinder? . a. 0.090 kN b. 0.10 kN c. 0.24 kN * d. 0.90 kN Refrigeration /Airconditioning System 26. A refrigeration system consumed 28,800 kw-hr per month of energy. There are 20% of energy is lost due to cooling system of the compressor and motor efficiency is 90%. If COP of the system is 6, find the tons of refrigeration of the system. a. 44.15 TR b. 49.15 TR* c. 46.15 TR d. 40.15 TR

27.

If the energy efficiency ratio of the refrigeration system is 12.6 , what is the cop of the system? a.3.69* b. 4.23 c. 5.91 d. 6.83 28.

A refrigeration plant is rated at 15 tons capacity. How many pounds of air per hour will it cool from 70 to 90oF at constant pressure. a. 50,100 lb/hr b. 52,100 lb/hr c. 37,500 lb/hr* d. 45,100 lb/hr 29. Consider a refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigeration has a COP of 1.3 and the cost of electricity is 8 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed. a. P49.59*

b. P42.59 c. P44.59 d. P40.59 30. A 75 hp motor that has a n efficiency of 91% is worn out and is replaced by a high-efficiency motor that has an efficiency of 95.4%. Determine the reduction in heat gain in the room due to higher efficiency under full-load conditions. a. 2.25 KW b. 2.65 KW c. 2.44 KW * d. 2.85 KW 31. A household refrigerator that has a power input of 450 watts and a COP of 2.5 is to cool five large watermelons, 10 kg each, to 8C. If the watermelons are initially at 20C, determine how long will it take for the refrigerator cool them. The watermelons can be treated as water whose specific heat is 4.2 KJ/kg-K. a. 2210 seconds b. 2240 seconds * c. 2230 seconds d. 2250 seconds 32. When a man returns to his wall-sealed house on a summer day, he finds that the house is at 32˚C. He returns on the air conditioner which cools the entire house to 20 deg C in 15 minutes. If COP is 2.5, determine the power drawn by the airconditioner. Assume the entire mass within the house is 800 kg of air for which Cv = 0.72 KJ/kg-K1Cp = 1.0 KJ/kg-K a. 1.172 KW b. 3.072 KW* c. 2.072 KW d. 4.072 KW 33. A heat source 800 deg K losses 2000 of heat to a sink at 500 deg K. Determine the entropy generated during this process. a. 1.5 KJ/K* b. -2.5 KJ/K c. 2.5 KJ/K d. 3 KJ/K 34. A supply of 50 kg chicken at 6 deg C contained in a box is to be frozen to 18 deg C in a freezer.

Determine the amount of heat that needs to be removed. The latent heat of the chicken is 247 KJ/kg, and its specific heat is 3.32 KJ/kg-C above freezing and 1.77 KJ/kg-C below freezing. The

container box is 1.5 kg, and the specific heat of the box material is 1.4 KJ/kg-C. Also the freezing temperature of chicken is -2.8 deg C. a. 15,206.4 KJ* b. 15,155 KJ c. 50.4 KJ d. 1,862 KJ 35. In order to cool 1 ton (1000 kg) of water at 20 deg C in an insulated tank, a person pours 80 kg of ice at -5 deg C into the water. Determine the final equilibrium temperature in the tank. The melting temperature and the heat of fusion of ice at atmospheric pressure are 0 deg C and 333.7 KJ/kg, respectively. a. 12.43 deg C* b. 15.43 deg C c. 17.43 deg C d. 13.43 deg C 36. A 3000KW diesel electric power plant uses 3700 gallons in a 24 hour period. Oil is 25O API. What is the thermal efficiency of the engine based on the indicated power if the generator is 90% efficient and 95% mechanical efficiency is assumed? a. 47.85% b. 53.65%* c. 42.20% d. 61.98% 37. Consider a refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigeration has a COP of 1.3 and the cost of electricity is 8 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed. a. P49.59* b. P42.59 c. P44.59 d. P40.59 38. Determine the equipment standard air volume for 150 m 3/s of air having a dry bulb temperature of 15°C. a 153 m3/s* b. 163 m3/s c. 172 m3/s d. 183 m3/s 39. The mass of an outside air at 50°C in an air conditioning unit is 60 kg. Find the temperature after mixing with 40 kg with recirculated air at 35°C. a 44°C* b. 30°C c. 52°C d. 47°C

40. Find the sensible heat factor of an air-conditioning unit having a sensible heat load of 60 kW and latent heat load of 20 kW. a 70% b. 50% c. 75%* d. 85% 41. The mass of an outside air at 50°C in an air conditioning unit is 60 kg. Find the temperature after mixing if the outside air mixed with 40 kg with recirculated air at 35°C. a 44°C* b. 30°C c. 52°C d. 47°C 42. The ratio of the actual partial pressure of vapor and the saturation pressure of vapor corresponding to the actual temperature of the mixture. a Humidity ratio* c Specific humidity b Relative humidity d All of the above 43. The temperature of a moist air which is equal to the saturation temperature of the partial pressure of the vapor. a Dry-bulb temperature c Dew-point temperature* b Wet-bulb temperature d All of the above 44. At constant temperature, the absolute pressure of gas varies inversely as its volume. a Amagat’s law c Charles’ law b Boyle’s law* d None of the above 45. The term enthalpy a is only used for the properties of refrigerant vapor b is considered by Gibb’s Rule. c will measure, by its change, the quantity of heat added when refrigerant is vaporized at constant pressure* d defines the gas equation 46. When heat is added to moist air in an air-conditioning process a The wet-bulb temperature decreases b The water vapor pressure increases c The relative humility increases d The absolute humidity remains constant.* 47. The ton of refrigeration is a heat unit equivalent to a 3,413 Btu/hr c b 2545 Btu/hr d

990 Btu/hr 12,000 Btu/hr*

48. A form of thermal convection when the bulk of the fluid is moving relative to the heat transfer surface because such motion is usually caused by a blower, fan, or pump that is forcing the flow. a Slow convection c Thermal convection b Forced convection* d Free convection 49. A form of thermal convection when the motion of the fluid is due entirely to the buoyancy forces usually confined to a layer near the heated or cooled surface.

a b c d

Slow convection Forced convection Thermal convection Free convection*

50. An instrument used in the study of the properties of air. a Thermometer b Hydrometer c Psychrometer* d None of the above 51. 50 kg of cooling water per second enters the condenser at 25 °C and leaves at 50 °C. Find the heat carried away by water. a. 2040.45 kW c. 3140.27 kW b. 3220.55 kW d. 5233.74 kW* 52. Calculate the work needed in order to compress air in an insulated cylinder from 0.20 m 3 to 0.01 m3. Initial state at T1 = 68 °F and at atmospheric pressure. a 110.10 kJ c. 115.74 kJ* b 121.56 kJ d. 112.45 kJ 53. If the latent and sensible heat loads are 20 kW and 80 kW respectively, what is the sensible heat ratio? a 0.81* c. 0.80 b 0.66 d. 0.60 54. A window type air conditioner is rated with compressor power of 1 Hp. The unit has an EER of 11.1. Determine the maximum cooling capacity of the unit in TOR. a. 0.54 c. 0.691* b. 0.67 d. 0.520 55. A refrigeration plant is rated at 15 tons capacity. How many pounds of air per hour will it cool from 70 to 90oF at constant pressure. a. 51,000 lb/hr c. 53,000 lb/hr b. 37,500 lb/hr* d. 57,000 lb/hr 56.

A steam initially is saturated at 250C passed through a 12 cm steel pipe for a total distance of 200 m. the steam line is insulated with material having k = 10 W/m 2-K and thickness of 6 cm. the ambient temperature of 25C. Determine the surface film conductance of air if the moisture at the discharge end is 10% and steam rate is 0.13 kg/s. a

0.125 W/m2-C

b. 0.871 W/m2-C

c. 0.661 W/m2-C*

d. 0.453 W/m2-C

57.

At an average temperature of 110C, hot air flows through a 5 m pipe with outside diameter of 80 mm and pipe thickness is 1 cm. the temperature of the tube along its entire length is 24C. if the heat transfer is 650W, find the convective film coefficient, W/m2-C. a 0 b. 2 c. 3* d. 4

58.

The air contained in a room loses heat to the surroundings at a rate of 50 kJ/min while work is supplied to the room by computer. TV, and lights at a rate of 1.2 kW. what is the net amount of energy change in kJ of air in the room during a 30-minute period? a 0.36 b. 70 c. 660* d. 1000

59.

The hot combustible gasses of a furnace are separated from the ambient air and its surrounding, which are 28C, by a brick wall 120 mm thick. The brick has a thermal conductivity of 1.23 W/m-K and a surface emissivity of 0.82. at steady state conditions the outer surface temperature is 120C. air surface film conductance is 15 W/m 2-K. What is the total heat transmitted for 20 m2.

a. 42.15 kW*

b. 23.55 kW

c. 45.55 kW

d. 53.45 kW

60.

A counter flow heat exchanger is designed to heat fuel oil from 26C to 100C while the heating fluids enters at 138C and leaves at 105C. The fuel oil is 27 API and has a specific heat of 2.3 kJ/kg-K and enters the heat exchanger at the rate of 1000 gallons per hour.

Determine the heating surface if overall coefficient of heat transfer is 420 kcal/hr-m2-K.

a.

4.20 m2

b. 3.12 m2

c. 2.24 m2

d. 5.84 m2*

61. A fan using standard air condition can develop a static pressure head of 310 mm water gage.

If fan will operate at 93 deg C and 735 mm Hg, Find the new static pressure required. a. 150 mm WG b. 170 mm WG c. 241 mm WG* d. 466 mm WG 62. The volume flow of air delivered by fan is 20 m^3/sec and 180 mm water gage. The density of air is 1.185 kg/m^3 and the motor power needed to drive the fan is 44 kW. What is the fan efficiency? a. 70.26 % b. 80.26 %* c. 74.26 % d. 90.26 % 63. A fan is listed as having the following performances with standard air: Volume discharge – 120 m^3/sec Speed – 7.0 rps Static pressure – 310 mm WG Brake power required – 620 kW

The system duct will remain the same and the fan will discharge the same volume of 120 m^3/sec of air at 93 deg C and barometric pressure of 735 mm Hg wen its speed is7.0 rps. Find the brake power input and the static pressure required. a. 231 mm water b. 251 mm water c. 241 mm water * d. 260 mm water 64. Air enters a fan through a duct at a velocity of 6.3 m/s and an outlet static pressure of 2.5 cm of water less than the atmospheric pressure. The air leaves the fan through a duct at a velocity of 11.25 m/s and a discharge static pressure of 7.62 cm of water above the atmospheric pressure. If the specific weight of the air is 1.20 kg/m^3 and the fan delivers 9.45 m^3/sec, what is the fan efficiency when the power input to the fan is 13.75 kW at the coupling? a. 71.81%* b. 91.20% c. 81.34% d. 61.34% 65. A fan delivers 4.7 m^3/sec at a static pressure of 5.08 cm of water when operating at a speed of 400 rpm. The power input required is 2.963 kW. If 7.05 m^3/sec are desired in the same fan and installation, find the pressure in cm of water. a. 7.65 b. 17.40 c. 11.43* d. 6.08 66. An air compressor has a power of 40 kw at 4 % clearance. If clearance will increase to 70 %, what is the new power? a 70 kw b 40 kw* c 52 kw d 63 kw 67. A three stages air compressor compresses air from 100 kpa to 1000 kpa. Find the intercooler pressure between the first and second stage. a. 504.44 kpa b. 108.44 kpa c. 316.23 kpa d. 215.44 kpa* 68. A 10-stages air compressor compresses air from 100 kpa to 800 kpa. Find the intercooler pressure between 1st and 2nd stage. a. 283.84 kpa b. 113.11 kpa c. 123.11 kpa* d. 333.51 kpa

69. A 3-stages air compressor compresses air from 100 kpa to 700 kpa. Find the intercooler pressure between the 2nd and 3rd stage. a. 365.88 kpa* b. 375.88 kpa c. 386.88 kpa d. 395.88 kpa 70. The discharge pressure of an air compressor is 5 times the suction pressure. If volume flow at suction is 0.1 m3/sec, what is the suction pressure if compressor work is 19.57 kw? (use n=1.35) a. 97 kpa b. 98 kpa* c. 99 kpa d. 110 kpa 71. At 35% solution leaves the absorber and 30% solution enters the absorber. The heat removed from the absorber by cooling water is 547.6 Btu and ammonia is superheated by 10 ° . Find the pound per pound of ammonia gas from the evaporating coils. a. 10

b. 12

c. 13*

d. 14

72. Compute the air flow in ft3/min of mechanical ventilation required to exhaust an accumulation of refrigerant due to leaks of the system capable of revolving air from the machinery room for a mass of 4 lbs refrigerant. a. 200*

b. 210

c. 270

d. 230

73. A thermoelectric refrigerator that resembles a small ice chest is powered by a car battery, and has a COP of 0.10. If the refrigerator cools at 0.350L canned drink from 20 OC to 4OC in 30 min. determine the average electric power consumed by the thermoelectric refrigerator. a. b. c. d.

130 watts* 100 watts 120 watts 140 watts

74. A 4m x 5m x 6m room is to be heated by a baseboard resistance heater. It is desired that the resistance heater be able to raise the air temperature in the room from 7 to 23 oC within 15 minutes. Assuming no heat losses from the room and an atmospheric pressure of 100 kpa, determine the required power of the resistance heater. Assume constant specific heats at room temperature. a. b. c. d.

2.35 KW 1.91 KW* 4.55 KW 6.31 KW

75. An auditorium seating 1500 people is to be maintained at 80 ℉ dry bulb and 85 ℉ wet bulb temperature when outdoor air is at 91 ℉ dry bulb and 75 ℉ wet bulb.

Solar heat load is 110,000 Btu/hr and supply air at 60 ℉ ,

determine the amount of

supply air. a. 93,229.17 lb/hr* b. 83,229.17 lb/hr c. 74,229.17 lb/hr d. 63,229.17 lb/hr Power plant Engineering 76. An iron block weighs 5 Newton and has volume of 200 cm^3. What is the density of the block? a 2458 kg/m^3 b 2485 kg/m^3 c 2584 kg/m^3 d 2549 kg/m^3* 77. If air is at a pressure of 22.22 Psia and at temperature of 800 degR, what is the specific volume? a 11.2 ft^3/lbm b 33.0 ft^3/lbm c 13.3 ft^3/lbm* d 31.2 ft^3/lbm 78. The specific gravity of mercury is 13.55. what is the specific weight of mercury? a 120.9 Kn/m^3 b 129.2 Kn/m^3 c 132.9 Kn/m^3* d 190.2 Kn/m^3 79. In an air standard OTTO cycle, the clearance volume is 18% of the displacement volume.

Find the thermal efficiency. a. 0.52 b. 0.50 c. 0.53* d. 0.65 80. The condition at the beginning of compression in an OTTO engine operating on hot-air standard with k= 1.35 are 101.325 kPa, 0.05 cubic meter and 32C. The clearance is 8% and 15 kJ are added per cycle. Determine the mean effective pressure. a. 323.97 kPa* b. 423.97 kPa c. 223.97 kPa d. 522.97 kPa 81. The power developed by the pump is 30 kW. What is the percent decrease in power if speed will decrease by 40%. a 78.4%* b. 90.1% c. 65.3% d. 82.4%

82. A reciprocating pump has 350 mm x 400 mm cylinder running at 360 rpm. If percent slip is 10%, find the volumetric efficiency of the pump. a. 75%

b.80%

c. 90%*

d. 95%

83. A pump develops a power of 50 kW at 300 rpm with fluid specific gravity of 1.02 when impeller diameter is 150 mm. if increases to 650 rpm, impeller diameter of 120 mm and specific gravity of 0.8. Find the new power. a. 130.7 kW*

b. 204.19 kW

c. 207.23 kW

d. 302.23 kW

84. A pump has a specific speed of 42 and 600 rpm when it delivers 0.01 m 3/s. find the head developed by the pump. a.

583.45 ft

b. 813.45 ft

c. 658.79 ft

d. 1015.29 ft*

85. A boiler feed pump has a suction enthalpy of 2500 kJ/kg and exit of 505 kJ/kg. Find the velocity of the water in the flowing in the pump. a 310 m/s b. 53 m/s c. 200 m/s d. 100 m/s* 86. A boiler uses 2500 kg of coal per hour and air required for combustion is 16 kg per kg coal. If ash loss is 10%, determine the mass of gas entering thechimney. a. 42,250 kg/hr * b. 78,300 kg/hr c. 85,452 kg/hr d. 33,800 kg/hr 87. Draft, in inches of water differential pressure, is generated at the base of 100 foot stack filled with 500F gases (Assume same molecular weight as air due to differential sp.gr.)

Under ambient conditions of 14.7 psia and 68F, air sp.wt. is 0.075 lb/ft 3. The draft is nearest to: a. 0.35 in water b. 0.65 in water * c. 1.10 in water d. 1.50 in water 88. A steam generator with economizer and air heater has an overall draft loss of 25.78 cm of water. If the stack gases are at 177 DegC and if the atmosphere is at 101.3 Kpa and 28 DegC. What theoretical height of stack in meters is needed when no draft fan are used?

Assume that the gas constant for the flue gasses is the same as that for air. a. 810.10 b. 630.10 c. 651.10 * d. 670.10

89. A 5 m x 4 m x 4 m room has an air temperature of 32 oC (psat = 4.559 kPaa, hg = 2559.9 kJ/kg) and the pressure is 101 kPaa. The mass of water vapor in air is 2.5 kg with R v = 0.45 kJ/kg-oK. What is the relative humidity of the air? a. 94.08 %* b. 73.08 % c. 84.08 % d. 64.08 % 90. The approach and efficiency of cooling tower are 10 oC and 65 %, respectively. If the temperature of water leaving the tower is 27 oC, determine the temperature of water entering the tower. a. 53.57 oC b. 50.47 oC c. 45.57 oC* d. 55.75 oC 91. A solid cube material is 0.75 cm on each side. If it floats in oil of density 800 kg/m^3 with one-third of the block out of the oil, what is the density of the material of the cube? a. 533 kg/m^3 * b. 532 kg/m^3 c. 523 kg/m^3 d. 543 kg/m^3 92. A hollow cylinder 1 m in diameter and 2 m high weighs 2825 N. How many kN of lead weighing 110 kN/m^3 must be fastened to the outside bottom of the cylinder to make it float with 1.5 m submerged in water? a. 8.5 Kn * b. 5.5 kN c. 1.5 kN d. 9.5 kN 93. A 1 m x 1.5 m cylindrical tank is full of oil with SG = 0.92. Find the force acting at the bottom of the tank in dynes. a. 106.33 x 103 dynes b. 106.33 x 104 dynes c. 106.33 x 105 dynes d. 106.33 x 106 dynes* 94. Find the pressure at the 100 fathom depth of water in kpag. a. 1,793.96 kpag* b. 1,893.96 kpag c. 1,983.96 kpag d. 1,693.96 kpag 95. A gas bubble rising from the ocean floor is 1 inch in diameter at a depth of 50 feet. Given the sp.gravity of sea water is 1.03, the buoyant force in lbs being exerted on the bubble at this instant is nearest to: a. b.

0.014 0.020*

c. d.

0.076 0.14 96. A diesel power plant uses fuel with heating value of 43,000 kJ/kg. What is the density of the fuel at 250C? a. 841 kg/m3 b. 872 kg/m3 c. 970 kg/m3 * d. 940 kg/m3 97. In an air standard brayton cycle, the compressor receives air at 101.325 kPa, 21C and it leaves at 600kPa at the rate of 4kg/s. Det the turbine work if the temperature of the air entering the turbine is 1000C. a 3000 kW b 2700 kW c 2028 kW * d 3400 kW 98. What is the thermal efficiency of an air standard of Brayton cycle if the air enters and leaves the gas turbine at 1000 degK and 500 degK, respectively a 40.40% b 50.00%* c 45.50% d 54.85% 99. Steam flows through a nozzle at 400 ˚C and 1 Mpa (h=3263.9 KJ/kg) with velocity of 300 m/s. Find the stagnation enthalpy. a b c d

3300 KJ/kg 3290 KJ/kg 3320 KJ/kg 3309 KG/kg*

100.

Air flows through a nozzle at a speed of 350 m/s. Find stagnation enthalpy if entrance temperature is 200 ˚C. a 231.25 ˚C b 251.25 ˚C c 261.25 ˚C* d 271.25 ˚C 82. A turbo-charged, 16 cylinder, Vee type diesel engine has an air consumption of 3,000 kg/her per cylinder at rated load and speed. This air is drawn in through a filter by a centrifugal compressor directly connected to the exhaust gas turbine. The temperature of the air from the compressor is 145°C and a counter flow air cooler reduces the air temperature to 45°C before it goes to the engine suction header. Cooling water enters air cooler at 30°C and leaves at 38°C. Calculate the quantity of cooling water in m3/hr required to cool the total requirements of the engine at rated load and speed.

A. 144* B. 136 C. 123 D. 165 83. An oil heater heats 100 kg per minute of oil from 35°C to 100°C in a counter flow heat exchanger. The average specific heat of the oil is 2.5KJ/kg-°C. Exhaust gases used for heating enter the heater with an average specific heat of 1 KJ/kg-°C, a mass flow rate of 250 kg/min and an initial temperature of 200°C. The overall heat transfer coefficient is 75 W/m2-°C. Determine heating surface in square meters.

A. 30 B. 63 C. 40 D. 36* 84. Calculate the energy transfer rate across 6” wall of firebrick with a temperature differences across the wall of 50°C. The thermal conductivity of the firebrick is 0.95 Btu/hr-ft-°F at the temperature interest.

A. 285 W/m2 B. 369 W/m2* C. 112 W/m2 D. 429 W/m2 85. Water is flowing in a pipe with radius of 25.4 cm at a velocity of 5m/sec at the temperature in the pipe. The density and viscosity of the water are as follows: density = 997.9 kg/sec, viscosity = 1.131 Pa-s. What is the Reynolds Number for this situation?

A. 2241* B. 96.2 C. 3100 D. 1140 86. A plate – type solar energy collector with an absorbing surface covered by a glass plate is to receive an incident radiation of 1000 W/m2. The glass plate has a reflectivity of 0.12 and transmissivity of 0.80.The absorbing surface has an absorptivity of 0.90. The area of the collector is 5 m2. How much solar energy in watts is absorbed by the collector? a. 2580 b. 3600* c. 3410 d. 3167 COMBUSTION 87. There are 20 kg flue gas formed per kg of fuel oil burned in the combustion of a fuel oil C12H26. What is the excess air in percent? a. 20.17% b. 27.17%* c. 17.57 d. 15.17

88. If the theoretical air-fuel ratio is 15, what is the approximate higher heating value in KJ/kgfuel? a. 56755 KJ/kg b. 45765 KJ/kg c. 46755 KJ/kg* d. 55765 KJ/kg 89. A boiler burns fuel oil with 15% excess air. The fuel may be represented by C14H30.

Calculate the molal air-fuel ratio. a. 55.3 b. 117.69* c. 102.34 d. 17.14 90. A type of coal formed after anthracite. a. Lignite b. Bituminous c. Pear d. Graphite* 91. Determine the air- fuel ratio on a mass basis for the complete combustion of octane, with theoretical amount of air. a. 15.05 kgair/kgfuel* b. 13.55 kgair/kgfuel c. 11.87 kgair/kgfuel d. 17.93 kgair/kgfuel FLUID MECHANICS 92. What force is exerted by water jet 50 mm diameter if it strikes a wall at the rate of 15 m/s?

A. 342 N B. 442 N* C. 764 N D. 563 N 93. A 300 mm x 75 mm venture meter is inserted in a 300 mm diameter pipeline where water flows at 55 liters/s. Neglecting friction loss, compute the drop in pressure head from the inlet to the throat.

A. 8 m* B. 10 m C. 6 m D. 12 m 94. A jet of water 50 mm diameter with a velocity of 35 m/s is being discharged in a horizontal direction from a nozzle mounted on a fire truck. The force required to hold the nozzle stationary is: A. 1.34 KN B. 2.40 KN* C. 4.23 KN D. 3.23 KN

95. An open storage vessel has 3 m of oil (SG = 0.82) and 6 m of water. The pressure at the bottom is: A. 45 kpa B. 65 kpa C. 83 kpa* D. 92 kpa 96. Is a fluid property which refers to the intermolecular attraction by which the separate particles of the fluid are held together A Cohesion* B Surface tension C Adhesion D Hypertension REFRIGERATION AND AIRCONDITIONING 97. Refrigerant number R -744 is: a. Butane b. Carbon monoxide c. Propane d. Carbon dioxide* 98. Refrigerant number R- 1150 is: a. propylene b. ethane* c. ethane d. Methyl formate 99. Refrigerant number R-40 is: a. chlorodiflouromethane b. diflouromethane c. ammonia d. chloromethane* 100.

A coil in series with evaporator that is used to prevent the liquid refrigerant entering the compressor a. Accumulator b. Liquid condenser c. Drier loop* d. Liquid suction heat exchanger 101.

A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13 Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the refrigerating effect. e 52.25 Btu/lb f 54.48 Btu/lb* g 56.68 Btu/lb h 58.89 Btu/lb 102.

A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13

Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the rate of Freon-12 circulated. e 181.7 lb/min f 183.6 lb/min* g 185.3 lb/min h 187.9 lb/min 103.

A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13 Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the net work required per pound of Freon-12 circulated. e 10.09 Btu/lb f 11.09 Btu/lb * g 12.09 Btu/lb h 13.09 Btu/lb 104.

A cooling plant using Freon-12 as the refrigerant is to have a capacity of 50 tons when operating on the refrigerating cycle. Enthalpies are: h1=80.04 Btu/lb, h2=91.13 Btu/lb, h3=h4=25.56 Btu/lb. For this ideal plant cycle determine the coefficient of performance. e 3.91 f 4.91* g 5.91 h 6.91 105.

An auditorium is to be maintained at a temperature of 26°C dry bulb and 50% RH. Air is to be supplied at a temperature not lower than 15°C dry bulb. The sensible heat gain is 110 Kw and the latent heat gain is 37.5 KW. Take ventilating air as 25% by weight of the air from the room, and is at 35°C dry bulb and 60% RH. Determine the refrigeration capacity in tons?

A. 43.45 B. 54.23 C. 63.28* D. 76.34 106.

Fifty gallons per minute of water enters a cooling tower at 115°F. Atmospheric air at 60°F and 55% relative humidity enters the tower at 6,000 cfm and leaves at 90°F saturated. Determine the exit temperature of water, °F A. 56.33 B. 65.33 C. 76.61* D. 45.34 107.

The moisture removed from a material is 250 lb/hr and change of humidity ratio in dryer is 0.0175. Determine the fan capacity if specific volume of air entering is 35 ft3/lb.

A. 400,000 ft3/hr B. 450,000 ft3/hr C. 500,000 ft3/hr*

D. 550,000 ft3/hr 108.

Fifty gallons per minute of water enters a cooling tower at 115°F. Atmospheric air at 60°F and 55% relative humidity enters the tower at 6,000 cfm and leaves at 90°F saturated. Determine the volume of water that leaves the tower in gpm.

A. 32.34 B. 48.62* C. 34.23 D. 65.33 109.

The sensible heat load and latent heat load in an air conditioning system is 120 KW and 47 KW, respectively. What is the sensible heat factor?

A. 65.34% B. 29.45% C. 76.54% D. 71.86%* 110.

The total heat load and latent heat load of theater is 150 KW and 60 KW, respectively. Supply air is at 15°C and has a mass of 9 kg/sec. Determine the temperature to be maintained in the theater.

A. 20°C B. 25°C* C. 30°C D. 35°C 111.

A cooling tower has an efficiency of 65%. Water enters the tower at 55°C. The wet bulb temperature of surrounding air is 27°C. What is the temperature of water leaving the tower?

A. 36.8°C* B. 44.5°C C. 46.9°C D. 30.4°C 112.

Outside air of an air conditioning system is 25% of recirculated air. Determine the mass of outside air if mass of supply air is 15 kg/sec.

A. 1 kg/sec B. 2 kg/sec C. 3 kg/sec* D. 4 kg/sec 113.

Compute the heat to be removed from 110 kg of lean beef if it were to be cooled form 20°C to 4°C, after which it is to be frozen and cooled to -18°C. Specific heat above freezing is given as 3.23 KJ/kg°C and below freezing as 1.68 KG/kg-°C. Freezing point is -2.2°C and latent heat of fusion is 233 KJ/kg.

A. 32,455 KJ B. 23,455 KJ C. 36,437.5 KJ* D. 54,233.2 KJ

114.

Fish weighing 11,000 kg with a temperature of 20°C is brought to a cold storage and which shall be cooled to -10°C in 11 hours. Find the required plant refrigerating capacity in tons of refrigeration if the specific heat of fish is 0.7 above freezing and 0.3 below freezing point which is -3°C. The latent heat of freezing is 55.5 Kcal/kg.

A. 21.3 B. 24.38* C. 28.34 D. 32.12 115.

The heat rejected from the condenser is 200 KW. The mass flow of water entering is 5 kg/sec at 23°C. If the temperature between the condenser cooling water outlet and condenser temperature is 5°C, what is the condenser temp?

A. 30.56°C B. 39.94°C C. 35.78°C D. 37.67°C* 116.

Wet material, containing 220% moisture (dry basis) is to be dried at the rate of 1.5 kg/s in a continuous dryer to give a product containing 10% moisture (dry basis). Find the moisture removed. a. 3513.75 kg/hr b. 3543.75 kg/hr* c. 3593.55 kg/hr d. 3643.55 kg/hr 117.

Fifty kilogram of cooling tower per second enters the condenser 15˚C and leaves at 50˚C. Find the heat carried away by water. a. 2234.45 kW b. 7327.25 kW* c. 5340.65 kW d. 4140.25 kW 118.

Water enters the cooling tower at 45C. The approximate leaving water temperature is 30C. If the atmospheric condition is 25C wet bulb, determine the cooling effectiveness. e 75%* f 65% g 55% h 85% 119.

Compute the humidity ratio of air at 70% relative humidity and 25C when the barometric pressure is 101.325 kpa. From steam tables: Psat at 34C=3.169kPa a 0.014 kg water vapor/kg dry air* b 0.14 kg water vapor/kg dry air c 1.4 kg water vapor/kg dry air d 0.0014 kg water vapor/kg dry air 120.

The mass of an outside air at 50°C in an air conditioning unit is 60 kg. Find the temperature after mixing with 40 kg with recirculated air at 35°C. a. 35°C b. 44°C*

c. 59°C d. 33°C 121.

A refrigeration system is used to cooled water in the evaporator a 8 kg/s of water from 30C to 2C. Find the tons of performance required. a. 136.75 TOR b. 139.45 TOR c. 121.35 TOR d. 266.75 TOR* INDUSTRIAL PLANT ENGINEERING 122.

The only devices where the changes in kinetic energy are significant are the A. compressor B. pumps C. nozzles and diffusers * D. none of these 123.

Modern way of detecting air compressor leak is by using A. Soup and water B. Air leak detector C. Acoustic leak detector* D. Ammonia leak detector 124.

Only ____ of the turbine work output is required to operate the pump.

A. 0.01% B. 0.02% C. 0.03% D. 0.04%* 125.

An axial compressor having 33,000 hp of internal power has inlet conditions of 14.5 psia and 65F and discharge conditions of 160 psia and 647F. Calculate the pressure ratio. a 9 b 11* c 13 d 15 126.

An axial compressor having 33,000 hp of internal power has inlet conditions of 14.5 psia and 65F and discharge conditions of 160 psia and 647F. Calculate the isentropic discharge temperature. a 1042 R* b 1137 R c 942 R d 1235 R 127.

An axial compressor having 33,000 hp of internal power has inlet conditions of 14.5 psia and 65F and discharge conditions of 160 psia and 647F. Calculate the isentropic compression efficiency. a 81% b 85% c 89%*

d 94% 128.

An axial compressor having 33,000 hp of internal power has inlet conditions of 14.5 psia and 65F and discharge conditions of 160 psia and 647F. Calculate mass flow rate of air. a 9,132 lb/min b 10,020 lb/min* c 10,987 lb/min d 11,562 lb/min 129.

An axial compressor having 33,000 hp of internal power has inlet conditions of 14.5 psia and 65F and discharge conditions of 160 psia and 647F. Calculate the capacity of the unit. a 133,500 ft3/min* b 68,000 ft3/min c 112,420 ft3/min d 157,238 ft3/min 130.

A submersible pump delivers 350 gpm of water to a height of 5 ft from the ground. The pump were installed 150 ft below the ground level and draw down of 8 ft during the operation. If water level is 25 ft above the pump, determine the pump power.

A. 10.32 KW B. 9.271 KW* C. 8.65 KW D. 4.39 KW 131.

An Ocean – Thermal Energy Conversion power plant generates 10,000 KW using a warm surface water inlet temperature of 26C and a cold deep- water temperature of 15oC. On the basis of a 3C drop in the temperature of the warm water and a 3oC rise in the temperature of the cold water due to removal and addition of heat, calculate the power required in KW to pump the cold- deep water to the surface and through the system heat.

Assume a Carnot cycle efficiency and density of cold water to be 1000 kg/m3.

A. 335 B. 143 C. 487 D. 249* 132.

A two stage air compressor has an intercooler pressure of 3 kg/cm2. What is the discharge pressure if suction pressure is 1kg/cm2?

A. 3 kg/cm2 B. 9kg/cm2* C. 23 kg/cm2 D. 15 kg/cm2 133.

The piston speed of an air compressor is 140 m/min and has a volume displacement of 0.2m3/sec. Determine the diameter of compressor cylinder.

A. 500 mm B. 358 mm C. 467 mm* D. 246 mm

134.

A single acting compressor has a volumetric efficiency of 89%, operates at 500 rpm. It takes in air at 900 KPa and 30C and discharges it at 600 KPa. The air handled is 8 m3/min measured at discharge condition. If compression is isentropic, find mean effective pressure in KPa. A. 882.95 B. 233.34* C. 743.12 D. 569.37 135.

A piston positive-displacement pump (PDP) has 6-in diameter and a 2.5 in stroke.

Its crankshaft rotates at 300 rpm. Calculate its output at 94 percent volumetric efficiency. a. 11.53 cfm* b. 14.58 cfm c. 10.22 cfm d. 12.76 cfm 136.

An air compressor has a power of 65 kw at 8 % clearance. If clearance will increase to 60 %, what is the new power? a 65 kw* b 55 kw c 58 kw d 45 kw 137.

A three stages air compressor compresses air from 100 kpa to 1000 kpa. Find the intercooler pressure between the first and second stage.

A. 662.75 kpa B. 215.44 kpa* C. 477.88 kpa D. 325.55 kpa 138.

Carbon dioxide flows through a nozzle with a speed of 380 m/s. The entrance condition of nozzle is 250oC and 1200 kpa. Find the stagnation pressure.

A. 2,136.34 kpa * B. 2,146.34 kpa C. 2,156.34 kpa D. 2,166.34 kpa 139.

Air flows through a nozzle with temperature of entrance of 420oK stagnation temperature of 468oK. Find the mach number.

A. 0.824 B. 0.729 C. 0.768 D. 0.744* 140.

Steam flows through a nozzle at 400oC and 1 Mpa (h = 3263.9 KJ/kg) with velocity of 300 m/s. Find the stagnation enthalpy.

A. 3309 KJ/kg* B. 3193 KJ/kg C. 3425 KJ/kg D. 3090 KJ/kg

141.

A reciprocating pump has 380 mm x 430 mm cylinder running at 360 rpm. If percent slip is 8%, find the volumetric efficiency of the pump. a 92%* b 90% c 94% d 88% 142.

What is the horsepower required for a fan to deliver 30 ft/sec of air through 2ft x 3 ft duct under a total pressure of 3in water gage? (density of air = 0.074lb/ft3) 5.44* 3.96 8.24 7.73 143.

In a boiler feed pump, the enthalpy at the entrance is 765 KJ/kg. If pump has a head of 900 m, what is the exit enthalpy of the pump.

A. 897 KJ/kg B. 465 KJ/kg C. 774 KJ/kg* D. 864 KJ/kg 144.

Water from a reservoir is pumped over a hill through a pipe 450 mm in diameter and a pressure of 1 kg/cm2 is maintained at the summit. Water discharge is 30m above the reservoir. The quantity pumped is 0.5 m3/sec. Frictional losses in the discharge and suction pipe and pump is equivalent to 1.5m head loss. The speed of the pump is 800 rpm what amount of energy must be furnished by the pump in KW? A. 202 B. 206* C. 204 D. 208 145.

A pump is to deliver 80 gpm of water at 140°F with a discharge pressure of 150 psig. Suction pressure indicates 2 inches of mercury vacuum. The diameter of suction and discharge pipes are 5 inches, respectively. The pump has an efficiency of 70%, while the motor efficiency is 80%. Determine power input to the drive motor.

A. 7.23 kw B. 2.34 kw C. 8.34 kw D. 9.39 kw* 146.

Determine the water horsepower of a centrifugal water pump which has an input of 3.5 Hp if the pump has an 8 inches nominal size suction and 6 inches nominal size discharge if it handles 150 gpm of water at 150°F. The suction line gage shows 4” Hg vacuum and the discharge gage shows 26 psi. The discharge gage is located 2 feet above the center of the discharge pipe line and pump inlet and discharge lines are at the same elevation.

A. 2.52 hp* B. 6.33 hp C. 4.23 hp

D. 8.34 hp POWER PLANT ENGINEERING 147.

At the beginning of the compression stroke an ideal Otto cycle has an air pressure of 15 psia, a temperature of 75F and a specific volume of 13.2 cubic feet per pound. At the end of compression the specific volume is 1.76 cubic feet per pound. The heat supplied to the cycle is 325 Btu/lb. Calculate the highest temperature of the cycle. e 3246 R* f 3346 R g 3478 R h 3198 R 148.

One pound of air at 100F is mixed with another pound of air at 40F. The mixing process is constant pressure with constant specific heat. Calculate the change of entropy for the lb of gas originally at 100F. e -0.01121 f -0.01321* g -0.02425 h -0.03525 149.

One pound of a certain working substance receives 100 Btu of heat at a constant temperature of 2000R. Calculate the change of entropy for the substance. a 0.05 Btu/lb-R* b 0.03 Btu/lb-R c 0.07 Btu/lb-R d 0.01 Btu/lb-R 150.

An Otto Cycle, with a 7 to 1 compression ratio, has 320 Btu/lb of heat supply. At the beginning of the compression process the pressure and temperature are 14.7 psia and 60F. Assuming constant specific heat, calculate the peak pressure. e 582 psi f 595 psi* g 603 psi h 614 psi 151.

A Diesel cycle has a 16 to 1 compression ratio and a peak cycle temperature of 2912R. Conditions at the beginning of compression are 14.7 psia and 60F. Assuming constant specific heat determine the net work. a 177 Btu/lb b 211 Btu/lb c 188 Btu/lb d 199 Btu/lb* 152.

A Brayton cycle with a pressure ratio of 6 has compressor inlet conditions of 70F and 14.7 psia. The turbine inlet temperature is equal to 1500F. Calculate the thermal efficiency of the basic cycle. a 38.55% b 40.10%* c 42.55%

d 45.10% 153.

A Rankine steam power cycle operates with steam at 600 psia and 850F from the boiler and a condenser pressure of 1 inch of mercury absolute. Enthalpies are h4=49.4Btu/lb, h1=1435.4 Btu/lb, s1=s2=1.6559 Btu/lb-R, h2=890.0Btu/lb, h3=47.1 Btu/lb, s4=s3=0.09146 Btu/lb-R. Determine the thermal efficiency. a 35.5% b 39.2%* c 42.3% d 44.4% 154.

All heavy machinery should be supported on ________ of sufficient mass and base area to prevent or minimize the transmission of vibrations.

A. Steel foundation B. Wooden foundations C. Solid foundations* D. Soil foundations 155.

Foundations mass should be from _______ times the weight of the machinery it is supposed to support.

A. 3 to 5* B. 5 to 7 C. 4 to 6 D. 1 to 2 156.

If the unbalanced inertia forces produced by the machine can be calculated, a mass weight equal to ________ times the forces should be used to dampen vibration.

A. 2 to 4 B. 5 to 6 C. 10 to 20* D. 10 to 15 157.

The diesel engine should not be placed on the foundation until 10 days have elapsed, nor operated until after another ________ days.

A. 7 B. 8 C. 9 D. 10* 158.

The safe soul bearing pressure of diesel engine foundations is: A. 2,600 kg/cm2 B. 4,890 kg/cm2* C. 5,633 kg/cm2 D. 2000 kg/cm2 159.

A steam generator with economizer and air heater has an overall draft loss of 21.78 cm of water. If the stack gases are at 177°C and if the atmosphere is at 101.3 Kpa

and 26°C, what theoretical height of stack in meters is needed when no draft fan are used? Assume that the gas constant for the flue gases is the same as that for air.

A. 565 B. 535 C. 545 D. 550* 160.

In a hydro-electric plant the brake power is 1800 KW running at 450 rpm and net head of 30 m. Determine the specific speed of the turbine.

A. 60.29 rpm B. 65.29 rpm C. 75.29 rpm D. 71.29 rpm* 161.

A boiler uses 2500 kg of coal per hour and air required for the combustion in 16 kg per kg coal. If ash loss is 10%, determine the mass of the gas entering the chimney.

A. 42,250 kg/hr* B. 78,300 kg/hr C. 85,452kg/hr D. 33,800 kg/hr 162.

The actual velocity of gas entering in a chimney is 8m/sec. The gas temperature is 25°C and pressure of 98 Kpa with a gas constant of 0.287 KJ/kg-°K. Determine the chimney diameter if mass of gas is 50,000 kg/hr.

A. 1.57 m B. 1.81 m C. 3.56 m D. 1.39 m* 163.

An air standard Brayton cycle has an air leaving the high-temperature heat exchanger at 850°C and leaving the turbine at 310°C. What is the thermal efficiency?

A. 42.21% B. 23.34% C. 48.08%* D. 56.34% 164.

A waste heat recovery boiler generates 250 kg/hr with hs – hf = 2300 KJ/kg. What is the exhaust loss from the engine if the actual heat developed is 35%?

A. 492.6 KW B. 365.7 KW C. 456.4 KW* D. 845.4 KW 165.

What is the displacement volume of 300 mm x 4400 mm, 4 – stroke, 1200 rpm, 8 cylinder diesel engine?

A. 0.243 m3/sec B. 2.262 m3/sec* C. 5.75 kg/sec D. 1.25 m3/sec 166.

A 16,000 KW geothermal plant has a generator efficiency and turbine efficiency of 90% and 80%, respectively. If the quality after throttling is 20% and each well

discharges 200,000 kg/hr, determine the number of wells are required to produce if the change in enthalpy at the entrance and exit of turbine is 500 KJ/kg.

A. 4 wells* B. 5 wells C. 6 wells D. 8 wells 167.

The annual energy produced in a 100 MW power plant is 438,000,000 KW – hrs.

What is the annual capacity factor of the plant?

A. 40% B. 50%* C. 35% D. 60% 168.

In Francis turbine, the pressure gage leading to the turbine casing reads 380 Kpa. The velocity of water entering the turbine is 8 m/sec, if net head of the turbine is 44 m, find the distance from center of spiral casing to the tailrace.

A. 2.0 m* B. 1.5 m C. 3.0 m D. 5.5 m 169.

A turbine has a mechanical efficiency of 93%, volumetric efficiency of 95% and total efficiency of 82%. If effective head is 45 m, find the total head.

A. 32.73 m B. 45.89 m C. 41.76 m* D. 35.88 m 170.

Steam turbine is receiving 1014 lbm/hr of steam, determine the horsepower output of the turbine if the work done by steam is 255 Btu/lbm A. 102 hp* B. 462.7 hp C. 200 hp D. 6002.7 hp 171.

In a cogeneration plant, steam enters the turbine at 4 Mpa and 4000C. One fourth of the steam is extracted from the turbine at 600 Kpa pressure for process heating. The remaining steam continues to expand to 10 Kpa. The extracted steam is then condensed and mixed with feedwater are constant pressure and the mixture is pumped to the boiler pressure of 4 Mpa. The mass flow rate of steam through the boiler is 30 kg/sec.

Disregarding any pressure drops and heat losses in the piping, and assuming the turbine and pump to be isentropic, how much process heat is required in KW? Steam properties: At 4 Mpa and 4000C: h = 3213.6 KJ/kg, s = 6.7690 At 600 Kpa: hf = 670.56 sf = 1.9312 hfg = 2086.3 sfg = 4.8288 A. 15,646.8* B. 2,458.2 C. 1.9312

D. 1,027.9 11. A heat exchanger has a hot gas temperature of 300°C and surface conductance on hot side is 200 W/m2-°K. If heat transmitted is 1000 W/m2, what is the surface temperature on the wall at hot side?

A. 295°C* B. 465°C C. 234°C D. 354°C 12. A heat exchanger is to be designed for the following specifications: Hot gas temperature, 1145°C Cold gas temperature is 45°C Unit surface conductance on the hot side, 230 W/m2-°K Unit surface conductance on the cold side, 290 W/m2-°K Thermal conductivity of the metal wall, 115 W/m-°K Find the maximum thickness of metal wall between the hot gas and cold gas, so that the maximum temperature of the wall does not exceed 545°C. A. 10 mm B. 30mm C. 20mm* D. 40mm 13. An uninsulated steam pipe passes through a room in which the air and walls are at 25°C. The outside diameter of the pipe is 70 mm, and its surface temperature and emissivity are 200°C and 0.80, respectively. If the coefficient associated with free convection heat transfer from the surface to the air is 15 W/m2-°K, what is the rate of heat loss from the surface per unit length of pipe?

A. 998 W/m2* B. 872 W/m2 C. 762 W/m2 D. 422 W/m2 14. A turbo-charged, 16 cylinder, Vee-type diesel engine has an air consumption of 3,000 kg/hr per cylinder at rated load and speed. This air is drawn in through a filter by a centrifugal compressor directly connected to the exhaust gas turbine. The temperature of the air from the compressor is 145°C and a counter flow air cooler reduces the air temperature to 45°C before it goes to the engine suction header. Cooling water enters air cooler at 30°C and leaves at 38°C. Calculate the log mean temperature difference.

A. 47°C* B. 87°C C. 34°C D. 65°C 15. A plate – type solar energy collector with an absorbing surface covered by a glass plate is to receive an incident radiation of 1200 W/m2. The glass plate has a reflectivity of 0.12 and transmissivity of 0.80.The absorbing surface has an absorptivity of 0.90. The area of the collector is 10 m2. How much solar energy in watts is absorbed by the collector? a. 8046

b. 8460 c. 8640* d. 6408 COMBUSTION 16. A fuel is represented with C5H8 is burned with 40% excess air. If mass of fuel is 0.17 kg, find the mass of air needed. a. 4.48 kg b. 3.38 kg* c. 1.638 kg d. 5.34 17. Is the largest group of coal containing 46-89% of fixed carbon and 20% to 40% volatile matter. a. Anthracite b. Sub-anthracite c. Bituminous * d. Subbituminous 18. By heating 1 gram of coal in an uncovered crucible until the coal is completely burned, the ____ will formed.

A. volatile matter and moisture B. ash * C. fixed carbon D. moisture content 19. A certain coal has the following ultimate analysis: C = 69% N2 = 5% H2 = 2.5% S = 7%.

Determine the amount of oxygen of the heating value of fuel is 26 961.45 KJ/kg. a. 4.5% b. 3.5%* c. 5.5% d. 2.5% 20. A bituminous coal has the following composition: C = 71.5% H = 5.0% O = 7.0% N = 1.3% S = 3% Ash =7.6% W = 3.4% Determine the theoretical weight of nitrogen in kgair/kgfuel of coal. a. 11.80 b. 9.80* c. 10.80 d. 8.80 FLUID MECHANICS 21. Hydraulic efficiency 85%, find Q in li/s. Power developed 10,500 kw under head of 320 m.

A. 3935* B. 3452 C. 3271 D. 3623

22. A fluid that has a velocity of 18 m/s will have an equivalent head of?

A. 16.51 m* B. 12.44 m C. 18.34 m D. 10.34 m 23. Determine the size of pipe which will deliver 5 liters of medium oil (v = 6.10 x 10-6 m2/s) assuming laminar flow conditions.

A. 522 mm* B. 454 mm C. 550 mm D. 650 mm 24. 19. The power available in a jet having a cross-sectional area of 0.005 m2 with a velocity of 25.80 m/s.

A. 34 kw B. 49 kw C. 43 kw* D. 23 kw 25. At any point in fluid at rest the pressure is the same in all directions. This principle is known as: a. Bernoulli principle b. Archimedes principle c. Pascal’s law* d. Torrecelli’s law REFRIGERATION AND AIRCONDITIONING 101.

Any device or portion of the equipment used to increase refrigerant pressure. a. Pressure vessel b. Pressure-imposing element* c. Pressure lift device d. Pressure limiting device 102.

Refers to blends compromising multiple components of different volatile that, when used in the refrigeration cycles, change volumetric composition and saturation temperature as they (evaporate) boil or condense at constant pressure a. isotropic b. blending c. composistion d. zeotropic* 103.

Is one secondary coolant is in direct contact with the air or other substance to be cooled or heated. a. Double indirect system spray b. Indirect closed system c. Indirect open spray system* d. Indirect vented closed system 104.

A refrigeration system has a capacity of 25 tons and rejects heat at the rate of 6560 Btu/min. Calculate the rate of heat absorption by the refrigerant.

a 3560 Btu/min b 6560 Btu/min c 5560 Btu/min d 5000 Btu/min * 105.

A refrigeration system has a capacity of 25 tons and rejects heat at the rate of 6560 Btu/min. Calculate the power required as input to the system,. a 1260 Btu/min b 1360 Btu/min c 1460 Btu/min d 1560 Btu/min* 106.

A refrigeration system has a capacity of 25 tons and rejects heat at the rate of 6560 Btu/min. Calculate the coefficient of performance for the system. a 1.6 b 2.2 c 2.8 d 3.2* 107.

The observed dry bulb temperature of atmospheric air is 80F and wet bulb temperature is 72F. Barometer is standard. Find the partial pressure of water vapor. a 0.2882 psia b 0.3452 psia* c 0.3952 psia d 0.4423 psia 108.

For atmospheric air, given: dry bulb temperature, 84 F; relative humidity, 54 percent. Determine the dew point temperature. a 63.32F b 64.41F c 65.54F* d 66.89F 109.

A refrigeration system consumed 28,800 kw-hr per month of energy. There are 20% of energy is lost due to cooling system of the compressor and motor efficiency is 90%. If COP of the system is 6, find the tons of refrigeration of the system. a. 40.32 TR b. 42.28 TR c. 45.97 TR d. 49.15 TR* 110.

A reversed Carnot cycle has a refrigerating COP of 2.5. Determine the ratio TH/TL? A.1.5 B.1.25 C.1.4* D.1.55 111.

Consider a refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigeration has a COP of 1.3 and the cost of electricity is 8 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed.

a. P43.59 b. P45.59 c. P47.59. d. P49.59* 112.

The power requirement of a Carnot refrigerator in maintaining a low temperature region at 300 K is 1.5 kW per ton. Find the heat rejected. a. 5.02 kW* b. 3.12 kW c. 7.42 kW d. 4.30 kW 113.

An ammonia ice plant operates between a condenser temperature of 35C and evaporator of -15C. It produces 10 metric ton of ice per day from water at 30C to ice at -5C. Assuming simple saturation cycle, determine the horsepower of the motor if the adiabatic efficiency of the compressor ec = 0.851 and mechanical efficiency em = 0.95.

The specific heat of ice is 2.094 kJ/kg-C and the latent heat is 335 kJ/kg. From the table of ammonia the following enthalpies are: condenser entrance = 1703 kJ/kg, exit = 366.1 kJ/kg; compressor entrance = 1443.9 kJ/kg, exit = 1703 kJ/kg. a. 17.58 hp b. 21.9 hp* c. 23.4 hp d. 25.6 hp 114.

A refrigeration system is used to cooled water in the evaporator a 8 kg/s of water from 30C to 2C. Find the tons of performance required. a. 136.75 TOR b. 139.45 TOR c. 121.35 TOR d. 266.75 TOR* 115.

Find the sensible heat factor of an air-conditioning unit having a sensible heat load of 90 kW and latent heat load of 40 kW. e 65.50% f 67.35% g 69.23%* h 71.45% 116.

Re-circulated air of 10 kg/s with 53 KJ/kg dry air enthalpy and outside air of 4 kg/s with 90KJ/kg dry air enthalpy enters the conditioning unit. Determine the air conditioning capacity of air conditioning apparatus if the supply enthalpy to conditioned space is 42 kJ/kg dry air. a. 184 KW b. 204 KW* c. 302 KW d. 154 KW 117.

Thirty kilogram of cooling tower per second enters the condenser 25˚C and leaves at 50˚C. Find the heat carried away by water. a 3140.25 kW* b 4231.68 kW

c 2555.55 kW d 2879.90 kW 118.

Copra enters a dryer containing 70% moisture and leaves at 7% moisture. Find the moisture removed on each pound of solid in the final product. a. 5.558 lb b. 2.258 lb* c. 4.458 lb d. 3.358 lb 119.

Wet material, containing 200% moisture (dry basis) is to be dried at the rate of 1.6 kg/s in a continuous dryer to give a product containing 10% moisture (dry basis). Find the moisture removed. a. 3333.55 kg/hr b. 3648.00 kg/hr* c. 3222.55 kg/hr d. 3948.00 kg/hr 120.

Water enters the cooling tower at 45C. The approximate leaving water temperature is 30C. If the atmospheric condition is 25C wet bulb, determine the range. a 15C* b 20C c 5C d 30C 121.

The density of R-12 refrigerant at compressor suction is 19.81 kg/m3. For mass flow rate of 2 kg/sec, determine the volume flow at suction.

A. 0.10 m3/sec* B. 0.25 m3/sec C. 0.30 m3/sec D. 0.40 m3/sec 122.

A 90 ton refrigeration system has a compressor input of 0.97 KW per ton refrigeration. If compressor efficiency is 75%, determine the heat rejected from the condenser.

A. 350 KW B. 260 KW C. 500 KW D. 382 KW * 123.

Milk must be received and cooled from 80°F to 38°F in 5 hrs. If 4000 gallons of fresh milk received having SG of 1.03 and cp = 0.935 Btu per lb-°F, find the refrigeration capacity.

A. 20 TR B. 30TR C. 22.5TR* D. 34.6 TR 124.

The temperature difference between the minimum and maximum temperature of Carnot cycle is 50°C. What is the minimum temperature if COP is 5.

A. 0.31°C* B. 2°C

C. 3°C D. 5°C 125.

Determine the heat to be removed from one ton of water at 26°C to an ice at -6°C. A. 215,765 KJ B. 413,956 KJ* C. 345,654 KJ D. 834,582 KJ INDUSTRIAL PLANT ENGINEERING 126.

In thermal power plant, forced draft fans are installed at the A. Foot of the stack B. Top of the stack C. Exit of the preheater D. Inlet of the preheater* 127.

Two types of fans are: A. centrifugal and axial * B. reciprocating and axial C. centrifugal and rotary D. tangential and rotary 128.

The only devices where the changes in kinetic energy are significant are the A. compressor B. pumps C. nozzles and diffusers * 129.

A centrifugal air compressor having an isentropic compression efficiency of 78% has inlet and discharge pressure of 100 kPa abs and 350 kPa abs, respectively. Inlet temperature to the unit 25C and the capacity measured at inlet is 1.0m3/sec. Determine the pressure ratio. a 2.5 b 3.5* c 4.5 d 5.5 130.

A centrifugal air compressor having an isentropic compression efficiency of 78% has inlet and discharge pressure of 100 kPa abs and 350 kPa abs, respectively. Inlet temperature to the unit 25C and the capacity measured at inlet is 1.0m3/sec. Determine the actual discharge temperature. a 425 K b 462 K* c 532 K d 572 K 131.

A centrifugal air compressor having an isentropic compression efficiency of 78% has inlet and discharge pressure of 100 kPa abs and 350 kPa abs, respectively. Inlet temperature to the unit 25C and the capacity measured at inlet is 1.0m3/sec. Determine the mass flow rate. a 1.17 kg/sec*

b 2.17 kg/sec c 3.17 kg/sec d 4.17 kg/sec 132.

A centrifugal air compressor having an isentropic compression efficiency of 78% has inlet and discharge pressure of 100 kPa abs and 350 kPa abs, respectively. Inlet temperature to the unit 25C and the capacity measured at inlet is 1.0m3/sec. Determine the internal compressor power, KW. a 193 KW * b 213 KW c 167 KW d 243 KW 133.

A vacuum pump is used to drain a flooded mine shaft of 20 water. The pump pressure of water at this temperature is 2.34 KPa. The pump is incapable of lifting the water higher than 16 m. What is the atmospheric pressure in kPa? A. 235.86 B. 122.44 C. 159.29* D. 99.89 134.

A double suction centrifugal pumps delivers 20 ft3/sec of water at a head of 12 m and running at 650 rpm. What is the specific speed of the pump?

A. 2770.72 rpm * B. 9255.16 rpm C. 5370.89 rpm D. 3883.69 rpm 135.

An air compressor delivers 0.23m3/s of water at 100 kpa and discharge to 650 kPa. Find the air power. a 36.35 kw b 45.23 kw c 40.23 kw d 56.92 kw* 136.

A steam generator with economizer and air heater has an overall draft loss of 25.78 cm of water. If the stack gases are at 177C and if the atmosphere is at 101.3 Kpa and 26C, what theoretical height of stack in meters is needed when no draft fan are used?

Assume that the gas constant for the flue gases is the same as that for air.

A. 651.10 * B. 633.59 C. 785.33 D. 697.78 137.

The piston speed of an air compressor is 140 m/min and has a volume displacement of 0.2m3/sec. Determine the diameter of compressor cylinder.

A. 500 mm B. 358 mm C. 467 mm* D. 246 mm

138.

A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a well 27 feet below the static water level. Drawdown when pumping at rated capacity is 10 feet. The pump delivers the water into a 25,000 gallons capacity overhead storage tank. Total discharge head developed by pump, including friction in piping is 243 feet. Calculate brake horsepower required to drive the pump if pump efficiency is 70%.

A. 31.31 B. 41.41 C. 21.21* D. 51.51 139.

A fan using standard air condition can develop a static pressure head of 310 mm water gage. If fan will operate 93°C and 735 mm of Hg, find the new static pressure required.

A. 150 mm water gage B. 180 mm water gage C. 241 mm water gage* D. 456 mm water gage 140.

A 10 Hp motor is used to drive an air compressor. The compressor efficiency is 75%. Determine the compressor work.

A. 6.0 KW* B. 6.5 KW C. 7.6 KW D. 5.6 KW 141.

A fan has a suction pressure of 30mm water vacuum with air velocity of 3m/sec.

The discharge has 150 mm of water gage and discharge velocity of 7m/sec. Determine the total head of fan if air density is 1.2 kg/m3.

A. 150 m B. 152 m* C. 154 m D. 156 m 142.

An air compressor takes air at 100 Kpa and discharges to 600 Kpa. If the volume flow of discharge is 1.2 m3/sec, determine the capacity of air compressor.

A. 4.32 m3/sec* B. 3.33 m3/sec C. 6.85 m3/sec D. 7.42m3/sec 143.

The total head of fan is 185m and has a static pressure of 210 mm of water gage, what is the velocity of air flowing if density of air is 1.15 kg/m3?

A. 6.85 m/sec* B. 3.45 m/sec C. 4.75 m/sec D. 8.54 m/sec 144.

At 1.2 kg/m3 air density a fan develops a brake power of 100 KW. It operates at 98 Kpa and 32°C with the same speed, what is the new brake power of the fan?

A. 68.4 KW B. 36.7 KW

C. 67.5 KW D. 93.3 KW* 145.

A double suction centrifugal pumps delivers 70 ft3/sec of water at a head of 12 m and running at 1250 rpm. What is the specific speed of the pump?

A. 5014 rpm B. 5453 rpm C. 2345 rpm D. 9968 rpm * 146.

The speed of a centrifugal pump is doubled. By what factor does the pump head change? a. 0.065 b. 4* c. 0.088 d. 2.5 147.

A piston positive-displacement pump (PDP) has 6-in diameter and a 2.5 in stroke.

Its crankshaft rotates at 300 rpm. Calculate its output at 94 percent volumetric efficiency. a. 11.53 cfm* b. 14.58 cfm c. 10.22 cfm d. 12.76 cfm 148.

The total head of fan is 187m and has a static pressure of 210mm of water gage, what is the velocity of air flowing if density of air is 1.15 kg/m^3 ? a. 9.281 m/sec * b. 7.43 m/sec c. 5.12 m/sec d. 3.35 m/sec 149.

A centrifugal pump requires 40 ft head to deliver water from low level to higher level. If pump speed is 1600 rpm, determine the impeller diameter of the centrifugal pump.

A. 185 mm* B. 160 mm C. 154 mm D. 176 mm 150.

An air compressor has a power of 40 kw at 4 % clearance. If clearance will increase to 70 %, what is the new power?

A. 65 kw B. 50 kw C. 53kw D. 40 kw* POWER PLANT ENGINEERING 151.

The foundation depth may be taken as good practical rule, to be ________ times the engine stroke.

A. 2.3 to 4.5 B. 3.2 to 4.2*

C. 3.2 to 5.2 D. 5.2 to 6.2 152.

Anchor bolts should be embedded in concrete of at least ________ times the bolt diameter.

A. 10 B. 20 C. 30* D. 40 153.

In a spark ignition engine the detonation occurs near the a. End of combustion* b. Middle of combustion c. Beginning of combustion d. Beginning of interaction 154.

In a compression ignition engine the detonation occurs near the a. End of combution b. Middle of combustion c. Beginning of combustion* d. Beginning of interaction 155.

At the beginning of the compression stroke an ideal Otto cycle has an air pressure of 15 psia, a temperature of 75F and a specific volume of 13.2 cubic feet per pound. At the end of compression the specific volume is 1.76 cubic feet per pound. The heat supplied to the cycle is 325 Btu/lb. Calculate the thermal efficiency. a 53.4 % b 58.7% c 55.4%* d 61.7% 156.

One pound of air at 100F is mixed with another pound of air at 40F. The mixing process is constant pressure with constant specific heat. Calculate the final mixture temperature. a 70F* b 80F c 90F d 100F 157.

One pound of a certain working substance receives 100 Btu of heat at a constant temperature of 2000R. Calculate the available energy at this latter temperature, the receiver temperature remaining 100F. a. 54 Btu/lb b. 74 Btu/lb c. 24 Btu/lb d. 44 Btu/lb* 158.

An Otto Cycle, with a 7 to 1 compression ratio, has 320 Btu/lb of heat supply. At the beginning of the compression process the pressure and temperature are 14.7 psia and 60F. Assuming constant specific heat, calculate the peak pressure. i 582 psi j 595 psi*

k 603 psi l 614 psi 159.

A Diesel cycle has a 16 to 1 compression ratio and a peak cycle temperature of 2912R. Conditions at the beginning of compression are 14.7 psia and 60F. Assuming constant specific heat determine the thermal efficiency. a 62.2%* b 65.5% c 58.8% d 53.3% 160.

A Rankine steam power cycle operates with steam at 600 psia and 850F from the boiler and a condenser pressure of 1 inch of mercury absolute. Enthalpies are h4=49.4Btu/lb, h1=1435.4 Btu/lb, s1=s2=1.6559 Btu/lb-R, h2=890.0Btu/lb, h3=47.1 Btu/lb, s4=s3=0.09146 Btu/lb-R. Determine the net work. a 842.9 Btu/lb b 1386 Btu/lb c 543.1 Btu/lb* d 545.4 Btu/lb 161.

The specific speed of turbine is 85 rpm and running at 450 rpm. If the head is 20 m and generator efficiency is 90%, what is the maximum power delivered by the generator? a. 563.91 KW b. 835.56 KW* c. 432.18 KW d. 782.19 KW 162.

The daily energy produced in a certain power is 280,000 KW – hrs. What is the daily average load?

A. 10 MW B. 15 MW C. 25 MW D. 20 MW* 163.

A power plant has a use factor of 50% and factor of 44%. How many hours did it operate during the year?

A. 7700 hrs.

B. 7800 hrs.

C. 7709 hrs.* D. 7805 hrs.

164.

A thermal power plant generates 5 MW has also 300 KW power needed for auxiliaries. If the heat generated by fuel is 13,000 KJ/sec, determine the net thermal efficiency.

A. 35.78% B. 36.15%*

C. 30.56% D. 33.67 165.

A water tube boiler has a heating surface area of 500 m2. For a developed boiler hp of 825. Determine the percent rating of the boiler.

A. 120.15% B. 160.15% C. 150.15%* D. 300.15% 166.

The actual specific evaporation of a certain boiler is 10. Factor of evaporation is 1.05. If the heating value of fuel is 30,000 KJ/kg, find the boiler efficiency.

A. 60%* B. 65% C. 70% D. 79% 167.

The ASME evaporation units of a boiler is 24,827,000 KJ/hr. The boiler auxiliaries consume 1.5 MW. What is the net boiler efficiency if the heat generated by the fuel is 30,000 KJ/kg?

A. 64.75%* B. 68.94% C. 62.76% D. 68.54% 168.

Ground water of geothermal power plant has an enthalpy of 700 KJ/kg and at turbine inlet is 2,750 KJ/kg and enthalpy of hot water in flash tank is 500 KJ/kg. What is the mass of steam flow entering the turbine if mass flow of ground water is 45 kg/sec?

A. 3.27 kg/sec B. 2.27 kg/sec C. 4.27 kg/sec* D. 9.27 kg/sec 169.

A foundation measures 3m x 4m x 5m. Find the yd3 of stone needed for a concrete mixture of 1:2:4.

A. 65.34 B. 56.45 C. 78.48 D. 69* 170.

A 16-cylinder V-type diesel engine is directly coupled to a 5000 KW AC generator. If generator efficiency is 90%, calculate the brake horsepower of the engine.

A. 7447 Hp* B. 6468 Hp C. 8542 Hp D. 7665 Hp 171.

In a hydro-electric power the tail water level fixes at 480 m. The net head is 27 m and head loss is 4% of the gross head. What is the head water elevation?

A. 500.34 m B. 508.12 m* C. 456.34 m

D. 567.34 m 172.

Determine the friction power of an engine if the frictional torque developed is 0.3 KN.m running at 1200 rpm.

A. 40.6 KW B. 37.7 KW* C. 36.5 KW D. 50.3 KW 173.

The compressor for an actual gas turbine requires 300 KJ/kg of work to quadruple the inlet pressure. The inlet air temperature is 100°C. Determine the compressor air exit temperature.

A. 234°K B. 542°K C. 653°K D. 673°K* 174.

The actual velocity of gas entering in a chimney is 8m/sec. The gas temperature is 25°C and pressure of 98 Kpa with a gas constant of 0.287 KJ/kg-°K. Determine the chimney diameter if mass of gas is 50,000 kg/hr.

A. 1.57 m B. 1.81 m C. 3.56 m D. 1.39 m* 175.

If the actual draft required for a furnace is 6.239 cm of water and the frictional losses in the stack are 15% of the theoretical draft, calculate the required stack height in meters. Assume that the flue gas have an average temperature of 149°C and molecular weight of 30. Assume air temperature of 21°C. A. 215 B. 230 C. 220* D. 210 16. Sea water for cooling enters a condenser at 27°C and leaves at 37°C. The condenser temperature is 45°C, what is the log mean temperature difference?

A. 50.65°C B. 12.33°C* C. 37.82°C D. 80.54°C 17. Determine the thermal conductivity of a material that uses a 2 m2 test panel, 25 mm thick with a temperature difference of 10.8°F between the surfaces. During the 5 hours test period, the heat transmitted is 200 KJ. A. 0.045 W/m-°K B. 0.560 W/m-°K C. 0.023 W/m-°K* D. 0.370 W/m-°K

18. A steam pipe having a surface temperature of 200 °C passes through a room where the temperature is 27°C. The outside diameter of pipe is 80 mm and emissivity factor is 0.8 Calculate the radiated heat loss for 3 m pipe length.

A. 1434.47 W* B. 2746.35 W C. 2756.57 W D. 3546.45 W 19. A counter flow heat exchanger is designed to heat fuel oil from 30°C to 90°C while the heating fluid enters at 140°C at 105°C. Determine the arithmetic mean temperature difference.

A. 72.5°C B. 62.5°C* C. 45.5°C D. 67.5°C 20. A heat exchanger has an overall coefficient of heat transfer of 0.50 KW/m2-°C. Heat loss is 11 KW and the mean temperature difference is 15°C. What is the heat transfer are in ft2?

A. 51.80 ft2 B. 37.30 ft2 C. 56.80 ft2 D. 15.80 ft2* COMBUSTION 21. A typical industrial fuel oil, C16H32 with 20% excess air by weight. Assuming complete oxidation of the fuel, calculate the actual air-fuel ratio by weight. a. 17.65 kgair/kgfuel* b. 13.45 kgair/kgfuel c. 19.45 kgair/kgfuel d. 21.65 kgair/kgfuel 22. Calculate the minimum volume of day tank 28API fuel having a fuel consumption of 1 kg/s. a. 94.71 m3 b. 97.41 m3 * c. 91.74 m3 d. 79.41 m3 23. A type of coal formed after anthracite. a. Lignite b. Bituminous c. Pear d. Graphite* 24. Which of the following helps in the ignition of coal?

A. Moisture B. Ash C. Fixed carbon D. Volatile matter*

25. Process used commercially in coal liquefaction a. Tropsch process b. Fisher process c. Fisher-Tropsch process* d. Mitch-Tropsch process FLUID MECHANICS 26. An air bubble rises from the bottom of a well where the temperature is 25°C, to the surface where the temperature is 27°C. Find the percent increase in volume of the bubble if the depth of the well is 5m. Atmospheric pressure is 101.528 Kpa. A. 49.3* B. 31.3 C. 56.7 D. 38.6 27. An empty, open can is 30 cm high with a 10-cm diameter. The can, with the open end down, is pushed under water with a density of 1000 kg/m3. Find the water level in the can when the top of the can is 50 cm below the surface.

A. 17.20 cm B. 2.12 cm* C. 4.20 cm D. 5.87 cm 28. A 24 inches long rod floats vertically in water. It has a 1 sq. in. cross section and has a specific gravity of 0.6. What length L is submerged?

A. 14.4 in* B. 2.4 in C. 9.6 in D. 18.0 in 29. Flow of water taking over in a pipe having a velocity of 10 m/s. Determine the velocity head of the water.

A. 50.1 m B. 5.1 m* C. 8.2 m D. 100m 30. The length of pipe is 168 meters. If the pressure drop is 50 Kpa for every 30 meters, what is the total pressure drop?

A. 260 kpa B. 300 kpa C. 280 kpa* D. 100 kpa REFRIGERATION AND AIRCONDITIONING 176.

Cascade refrigeration cycle is often used in the industrial process where objects must be cooled condenser to the temperature below: a. -46 C*

b. -56 C c.- 66C d. -76 C 177.

Type of refrigerant control designed to maintain a pressure difference while the compressor is operating. a Thermostatic expansion valve b Using low side float flooded sytem c Automatic expansion valve d Capillary tube* 178.

Refrigerants consisting of mixture of two or more different chemical compounds, often used individually as refrigerants for other applications. a. Suspension b. Compound reaction c. Blends* d. Mixing of refrigerants 179.

Calculate the horsepower required per ton of refrigeration produced by the reversal of a Carnot Cycle having a thermal efficiency of 50 percent. a 2.71 hp b 3.71 hp c 4.71 hp* d 5.71 hp 180.

A refrigerating plant for an air-conditioning system is to have a capacity of 10 tons and a coefficient of performance of 2.50 when operating with a refrigerating effect of 61.4 Btu/lb of refrigerant. Calculate the refrigerant flow rate. a 30.4 lb/min b 31.8 lb/min c 32.6 lb/min* d 33.9 lb/min 181.

A refrigerating plant for an air-conditioning system is to have a capacity of 10 tons and a coefficient of performance of 2.50 when operating with a refrigerating effect of 61.4 Btu/lb of refrigerant. Calculate the work done on refrigerant by the compressor. a 22.7 Btu/lb b 23.9 Btu/lb c 24.6 Btu/lb* d 25.4 Btu/lb 182.

A refrigerating plant for an air-conditioning system is to have a capacity of 10 tons and a coefficient of performance of 2.50 when operating with a refrigerating effect of 61.4 Btu/lb of refrigerant. Calculate the compressor internal horsepower. a 16.9 hp b 17.5 hp c 18.9 hp* d 19.5 hp 183.

A refrigerating plant for an air-conditioning system is to have a capacity of 10 tons and a coefficient of performance of 2.50 when operating with a refrigerating effect of 61.4 Btu/lb of refrigerant. Calculate the rate of heat rejection from the system.

a 1400 Btu/min b 2000 Btu/min c 2800 Btu/min* d 4200 Btu/min 184.

The observed dry bulb temperature of atmospheric air is 80F and wet bulb temperature is 72F. Barometer is standard. Find the pounds of water vapor per pound of dry air. a 0.01496 lb/lb* b 0.01327 lb/lb c 0.01652 lb/lb d 0.01232 lb/lb 185.

For atmospheric air, given: dry bulb temperature, 84 F; relative humidity, 54 percent. Determine the enthalpy of dry air. a. 32 Btu/lb b. 33 Btu/lb c. 34 Btu/lb d. 35 Btu/lb* 186.

An ammonia simple saturation cycle operates with a suction pressure of 291.6 kPa and a condenser pressure of 1204 kPa develops 15 tons of refrigeration. Determine the theoretical horsepower of the compressor. The following enthalpies have been found at the condenser entrance = 1653 kJ/kg, exit = 346.6 kJ/kg, compressor entrance 1450.2 kJ/kg, exit = 1653 kJ/kg. a. 13 hp* b. 15 hp c. 18 hp d. 23 hp 187.

A reversed Carnot cycle has a refrigerating COP of 1.5. Determine the ratio TH/TL? A.1.667* B.1.252 C.1.501 D.1.333 188.

Consider a refrigeration whose 40 watts light bulb remains on continuously as a result of a malfunction of the switch. If the refrigeration has a COP of 1.3 and the cost of electricity is 8 cents per kw-hr, determine the increase in the energy consumption of the refrigerator and its cost per year if the switch is not fixed. a. P43.59 b. P45.59 c. P47.59. d. P49.59* 189.

The power requirement of a Carnot refrigerator in maintaining a low temperature region at 300 K is 1.5 kW per ton. Find the heat rejected. a. 5.02 kW* b. 3.12 kW c. 7.42 kW

d. 4.30 kW 190.

A Carnot refrigerator operates in a room in which the temperature is 25C and consumes 2 kW of power when operating. If the food compartment of the refrigerator is to be maintained at 3C, determine the rate of heat removal from the food compartment.

A. 2216.8 kJ/min B. 128.6 kJ/min C. 1504.8 kJ/min* D. 109.57 kJ/min 191.

Compute the humidity ratio of air at 70% relative humidity and 25C when the barometric pressure is 101.325 kpa. From steam tables: Psat at 34C=3.169kPa e 0.014 kg water vapor/kg dry air* f 0.14 kg water vapor/kg dry air g 1.4 kg water vapor/kg dry air h 0.0014 kg water vapor/kg dry air 192.

Find the sensible heat factor of an air-conditioning unit having a sensible heat load of 60 kW and latent heat load of 20 kW. a. 75%* b. 60% c. 55% d. 95% 193.

Fifty gallons per minute of water enters a cooling tower at 115°F. Atmospheric air at 60°F and 55% relative humidity enters the tower at 6,000 cfm and leaves at 90°F saturated. Determine the exit temperature of water, °F A. 56.33 B. 65.33 C. 76.61* D. 45.34 194.

The change of enthalpy in a heating chamber of dryer is 25 Btu and the mass of air supplied is 30,000 lb/hr. What is the heat supplied by heater?

A. 560 KW B. 450 KW C. 350 KW D. 220 KW* 195.

The moisture removed from a material is 250 lb/hr and change of humidity ratio in dryer is 0.0175. Determine the fan capacity if specific volume of air entering is 35 ft3/lb.

A. 400,000 ft3/hr B. 450,000 ft3/hr C. 500,000 ft3/hr* D. 550,000 ft3/hr 196.

A cooling tower has an efficiency of 65%. Water enters the tower at 55°C. The wet bulb temperature of surrounding air is 27°C. What is the temperature of water leaving the tower?

A. 36.8°C* B. 44.5°C

C. 46.9°C D. 30.4°C 197.

Recirculated air of 8 kg/sec with 53 KJ/kg enthalpy and outside air of 2 kg/sec with 90 KJ/kg enthalpy enters the conditioning unit. Determine the air conditioning capacity if supply enthalpy to conditioned space is 42 KJ/kg.

A. 154 KW B. 164 KW C. 174 KW D. 184 KW* 198.

A refrigeration compressor has a specific volume of 0.0482 m3/kg entrance and 0.017 m3/kg at exit. If volumetric efficiency is 90%, determine the percent clearance of the compressor.

A. 5.45%* B. 6.35% C. 10% D. 12% 199.

A 100 ton refrigeration system is used to produce chilled water from 22°C to 2°C. Determine the volume flow of water in li/sec.

A. 3.0 B. 3.5 C. 4.2* D. 5.5 200.

The refrigerating effect of 100 tons refrigeration is 117 KJ/kg. Determine the mass flow of refrigerant.

A. 1kg/sec B. 2kg/sec C. 3 kg/sec* D. 4 kg/sec INDUSTRIAL PLANT ENGINEERING 201.

Type of lubrication system in diesel engine in which oil from pump is carried to a separate storage tank outside the engine cylinder and used for high capacity engine.

A. Mist lubrication system B. Wet pump lubrication system C. Splash system D. Dry sump lubrication system* 202.

A type of turbine used for driving pumps, fans, and other auxiliaries in power plant commonly operate at exhaust pressure approximating atmospheric A. Tandem compound turbine B. Passout turbine C. Cross-compound turbine D. Back pressure turbine* 203.

When the air duct system serves several enclosed spaces, the permissible quantity of refrigerant in the system shall not exceed the amount determined by using the total

volume of those spaces in which the airflow cannot be reduced to less than of its maximum when the fan is operating.

A. One-quarter* B. One half-quarter C. Three-quarter D. One fourth-quarter 204.

An axial compressor with an isentropic compression efficiency of 83% has an internal power of 65 hp and an overall pressure ratio of 10. Inlet conditions are 14.6 psia and 60F. Determine the discharge pressure. a 135 psia b 146 psia * c 157 psia d 158 psia 205.

An axial compressor with an isentropic compression efficiency of 83% has an internal power of 65 hp and an overall pressure ratio of 10. Inlet conditions are 14.6 psia and 60F. Determine the isentropic discharge temperature. a 1004 R* b 1078 R c 987 R d 956 R 206.

An axial compressor with an isentropic compression efficiency of 83% has an internal power of 65 hp and an overall pressure ratio of 10. Inlet conditions are 14.6 psia and 60F. Determine the actual discharge temperature. a 1103 R* b 1235 R c 1198 R d 1035 R 207.

An axial compressor with an isentropic compression efficiency of 83% has an internal power of 65 hp and an overall pressure ratio of 10. Inlet conditions are 14.6 psia and 60F. Determine the mass flow rate. a 18.7 lb/min b 20.7 lb/min c 16.7 lb/min d 19.7 lb/min* 208.

An axial compressor with an isentropic compression efficiency of 83% has an internal power of 65 hp and an overall pressure ratio of 10. Inlet conditions are 14.6 psia and 60F. Determine the capacity. a 240 ft3/min b 250 ft3/min c 260 ft3/min* d 270 ft3/min 209.

A vacuum pump is used to drain a flooded mine shaft of 20 water. The pump pressure of water at this temperature is 2.34 KPa. The pump is incapable of lifting the water higher than 16 m. What is the atmospheric pressure in kPa? A. 235.86

B. 122.44 C. 159.29* D. 99.89 210.

A submersible, multi-stage, centrifugal deep well pump 260 gpm capacity is installed in a well 27 feet below the static water level and running at 3000 rpm.

Drawdown when pumping at rated capacity is 10 feet. The pump delivers the water into a 25,000 gallons capacity overhead storage tank. Total discharge head developed by pump, including friction in piping is 243 feet. Calculate the diameter of the impeller of this pump in inches if each impeller diameter developed a head of 38 ft. a. 3.71* b. 2.76 c. 4.32 d. 8.11 211.

An Ocean – Thermal Energy Conversion power plant generates 10,000 KW using a warm surface water inlet temperature of 26C and a cold deep- water temperature of 15oC. On the basis of a 3C drop in the temperature of the warm water and a 3oC rise in the temperature of the cold water due to removal and addition of heat, calculate the power required in KW to pump the cold- deep water to the surface and through the system heat.

Assume a Carnot cycle efficiency and density of cold water to be 1000 kg/m3.

A. 335 B. 143 C. 487 D. 249* 212.

A simple Rankine cycle produces 40 MW of power, 50 MW of process heated and rejects 50 MW of heat to the surroundings. What is the utilization factor of this cogeneration cycle neglecting the pump work?

A. 64% * B. 55% C. 69% D. 75% 213.

A fan is powered by a 0.5 hp motor and delivers air at a rate of 85 m3/min.

Determine the highest value for the average velocity of air mobilized by the fan. The density of air is 1.18 kg/m3.

A. 24.27 m/s B. 29.66 m/s C. 18.99 m/s D. 21.13 m/s* 214.

An air compressor delivers 0.23m3/s of water at 100 kpa and discharge to 650 kPa. Find the air power. e 36.35 kw f 45.23 kw g 40.23 kw h 56.92 kw*

215.

A single stage compressor has an initial pressure of 98 kpa and compresses to 800 kpa with suction volume 0.2m3/s. Using PV1.34=C, find the percent decrease in power due to two staging. a 14.23% b 10.23% c 18.34% d 13.23%* 216.

An air compressor takes air at 101 kpa at the rate of 0.5 m3/s and discharges to 600 kpa. If power input to the compressor is 130 kw, determine the heat loss in the compressor. a 18.34 kw b 12.68 kw * c 6.23 kw d 10.34 kw * 217.

A fan has a power output of 100kw. The fan efficiency is 70%. Find the horsepower output of the motor needed to drive the fan. a 142.86 b 191.50* c 123.45 d 165.56 218.

A 10-stages air compressor compresses air from 100 kpa to 800 kpa. Find the intercooler pressure between the 1st and 2nd stage. a 282.84 kPa b 113.21 kPa c 123.11 kPa* d 333.51 kPa 219.

The volumetric efficiency of a pump is 90%, what is the slip? a. 0.23 c. 0.092 b. 0.0422 d. 0.10* 220.

Carbon dioxide flows through a nozzle with a speed of 400 m/s. Compute the dynamic temperature.

A. 92.56K B. 94.56K * C. 96.56K D. 98.56K 221.

A double suction centrifugal pumps delivers 70 ft3/sec of water at a head of 12 m and running at 1250 rpm. What is the specific speed of the pump?

A. 5014 rpm B. 5453 rpm C. 2345 rpm D. 9968 rpm *

222.

The pump centerline of a centrifugal pump is located 2.5 m above from the high tide level. The sea water varies two meters from high tide to low tide level. If friction loss at the suction is 0.8 m, determine the total suction head.

A. 5.30 m* B. 2.30 m C. 6.30 m D. 8.23 m 223.

Determine the number of stages needed for a centrifugal pump if it is used to deliver 400 gal/min of water and pump power of 15 Hp. Each impeller develops a head of 38 ft.

A. 6 B. 4* C. 8 D. 7 224.

A pump is used to deliver 50 li/sec of sea water at a speed of 120 rpm. If speed will increase to 135 rpm, determine the increase in pump capacity.

A. 56.25 li/sec B. 34.56 li/sec C. 87.54 li/sec D. 6.260 li/sec* 225.

A fan draws 1.42 m3 per second of air at a static pressure of 2/54 cm water through a duct 300mm diameter and discharges it through a duct of 275mm diameter.

Determine the static fan efficiency if total fan mechanical is 70% and air is measured at 25°C and 760 mm Hg. A. 50.11%* B. 54.34% C. 65.37% D. 45.34% POWER PLANT ENGINEERING 226.

When process steam is basic need and power is by product, this cycle is known as: a. Cogeneration cycle b. Combined cycle c. By-product cycle* d. Cascading cycle 227.

A cycle typically used in paper mills, textile mills, chemical factories, sugar factories and rice mills a. Cogeneration cycle* b. Combined cycle c. By- product cycle d. Regenerative heater 228.

Also known as daerator a. Open heater*

b. Closed heater c. Mono heater d. Regenerative heater 229.

Type of turbine that has a specific speed below 5. a. Impulse turbine* b. Francis turbine c. Propeller turbine d. Deriaz turbine 230.

At the beginning of the compression stroke an ideal Otto cycle has an air pressure of 15 psia, a temperature of 75F and a specific volume of 13.2 cubic feet per pound. At the end of compression the specific volume is 1.76 cubic feet per pound. The heat supplied to the cycle is 325 Btu/lb. Calculate the highest pressure of the cycle. a 685 psia* b 620 psia c 735 psia d 783 psia 231.

One pound of air at 100F is mixed with another pound of air at 40F. The mixing process is constant pressure with constant specific heat. Calculate the change of entropy for the lb of gas originally at 40F. a +0.01123 b +0.02342 c +0.01398* d +0.01527 232.

One pound of a certain working substance receives 100 Btu of heat at a constant temperature of 2000R. Calculate the change of entropy for 100 Btu added to 1 lb of the same substance at 1000R. a +0.05 b +0.08 c +0.10* d +0.15 233.

An Otto Cycle, with a 7 to 1 compression ratio, has 320 Btu/lb of heat supply. At the beginning of the compression process the pressure and temperature are 14.7 psia and 60F. Assuming constant specific heat, calculate the peak temperature. a 2542F* b 2387F c 2785F d 2132F 234.

A Diesel cycle has a 16 to 1 compression ratio and a peak cycle temperature of 2912R. Conditions at the beginning of compression are 14.7 psia and 60F. Assuming constant specific heat determine the net work. e 177 Btu/lb f 211 Btu/lb g 188 Btu/lb h 199 Btu/lb*

235.

A Brayton cycle with a pressure ratio of 6 has compressor inlet conditions of 70F and 14.7 psia. The turbine inlet temperature is equal to 1500F. Calculate the thermal efficiency of the basic cycle. e 38.55% f 40.10%* g 42.55% h 45.10% 236.

A Rankine steam power cycle operates with steam at 600 psia and 850F from the boiler and a condenser pressure of 1 inch of mercury absolute. Enthalpies are h4=49.4Btu/lb, h1=1435.4 Btu/lb, s1=s2=1.6559 Btu/lb-R, h2=890.0Btu/lb, h3=47.1 Btu/lb, s4=s3=0.09146 Btu/lb-R. Determine the heat rejected. a 1386 Btu/lb b 842.9 Btu/lb* c 543.1 Btu/lb d 545.4 Btu/lb 237.

A single acting, twin cylinder, Ammonia compressor with bore equal to stroke is driven by an engine at 250 rpm. The machine is installed in a chilling plant to produce 700 kW of refrigeration at -18 oC evaporating temperature. At this temperature the cooling effect per kg mass is 1160 kJ. The specific volume of vapour entering the compressor is 0.592 m3 per kilogram. Assume 85% volumetric efficiency, determine the bore in mm. a .650 mm c. 550 mm b. 400 mm* d. 380 mm 238.

A Pelton type turbine has 25 m head friction loss of 4.5 m. The coefficient of friction head loss (from Morse) is 0.00093 and penstock length of 80 m. What is the penstock diameter?

A. 1,355.73 mm * B. 3,476.12 mm C. 6771.23 mm D. 1686.73 mm 239.

Steam turbine is receiving 1014 lbm/hr of steam, determine the horsepower output of the turbine if the work done by steam is 255 Btu/lbm A. 102 hp* B. 462.7 hp C. 200 hp D. 6002.7 hp

240.

In Francis turbine, the pressure gage leading to the turbine casing reads 380 Kpa. The velocity of water entering the turbine is 8 m/sec, if net head of the turbine is 44 m, find the distance from center of spiral casing to the tailrace.

A. 2.0 m* B. 1.5 m C. 3.0 m D. 5.5 m 241.

A steam engine has 10% brake thermal efficiency and delivers 750 kg/hr steam.

The enthalpy of engine entrance is 2800 KJ/kg and condenser exit is 450 KJ/kg.

Determine the brake power of the engine. Answer C A. 46 KW B. 47 KW C. 49 KW* D. 48 KW 242.

A 16,000 KW geothermal plant has a generator efficiency and turbine efficiency of 90% and 80%, respectively. If the quality after throttling is 20% and each well discharges 200,000 kg/hr, determine the number of wells are required to produce if the change in enthalpy at the entrance and exit of turbine is 500 KJ/kg.

A. 4 wells* B. 5 wells C. 6 wells D. 8 wells 243.

A machine foundation has a trapezoidal cross-sectional with bases of 2m and 3m.

The height is 1.5 m and foundation length of 4m. Find the required yd3 of sand to be used for 1:2:4 mixture.

A. 7.33 B. 12.4 C. 9.34 D. 8.63* 244.

Determine the brake power of the engine having a brake thermal efficiency of 35% and uses 250API fuel consumption of 40 kg/hr.

A. 165.84 KW B. 173.52 KW* C. 194.55 KW D. 160.67 KW 245.

Determine the specific gravity of fuel oil having a heating value of 44,899.2 KJ/kg.

A. 0.90 B. 0.80 C. 0.877 D. 0.893* 246.

A steam engine has 10% brake thermal efficiency and delivers 750 kg/hr steam.

The enthalpy of engine entrance is 2800 KJ/kg and condenser exit is 450 KJ/kg.

Determine the brake power of the engine. Answer C A. 46 KW

B. 47 KW C. 49 KW* D. 48 KW 247.

Determine the specific gravity of fuel oil having a heating value of 44,899.2 KJ/kg.

A. 0.90 B. 0.80 C. 0.877 D. 0.893* 248.

In a hydro-electric power the tail water level fixes at 480 m. The net head is 27 m and head loss is 4% of the gross head. What is the head water elevation?

A. 500.34 m B. 508.12 m* C. 456.34 m D. 567.34 m 249.

The gas density of chimney is 0.75 kg/m3 and air density of 1.15 kg/m3. If the driving pressure is 0.25 Kpa, determine the height of chimney.

A. 54.6 m B. 63.7 m* C. 74.6 m D. 68.5 m 250.

A steam generator with economizer and air heater has an overall draft loss of 21.78 cm of water. If the stack gases are at 177°C and if the atmosphere is at 101.3 Kpa and 26°C, what theoretical height of stack in meters is needed when no draft fan are used? Assume that the gas constant for the flue gases is the same as that for air.

A. 565 B. 535 C. 545 D. 550*