HYDRODYNAMIC ANALYSIS OF JOURNAL BEARINGS USING CFD AND FSI TECHNIQUES
3Assistant Professor, Dept. of Mechanical Engineering, Kuppam Engineering College, AP, India ***
Key Words: fluid mechanics bearing, fluid interaction technique, CFD.
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1088
1PG Student, Dept. of Mechanical Engineering, Kuppam Engineering College, AP, India
Abstract Fluid mechanics journal bearings area unit vital power transmission elements for carrying high masses to extend power capability in varied machines. The precise operativeparametersareaunitessentialforfluidmechanics journalbearingstostylemachines.Associatedegreeoilfilm pressure is one amongst the key operative parameter to describingtheoperativeconditionsinfluidmechanicsjournal bearings.Inthisreport,theCFDanalysis,StaticandThermal analysiswasdoneonliquidgreasedcylindricalbearing.soas tosearchoutPressureprofileandtemperaturedistribution within the bearing structure, satisfying the boundary conditions. To analyzed the geometric and operative parameters, like Journal Eccentricity quantitative relation (0.2, 0.4, 0.6 and 0.8.) and motion Speed (3000rpm) mistreatmentAnsys. InJournalbearingsvariedparameterswerethought offormodelinglikelengthanddiameter(L/D)quantitative relation(0.8.)andeccentricityratios(0.2,0.4,0.6and0.8.) and were sculptural in 3D modeling software system Pro/Engineer.TheliquidstuffsSAE30&fortyoilwasthought of as lubricant to see stress, strain and deformation of a bearing. Journal bearing models was developed at speed of 3000 rate to review the interaction between the fluid and elasticbehavior ofthebearing.Thespeed isinputforCFD analysis and also the temperature and pressure obtained from the CFD analysis was taken as input for thermal and staticanalysis.Computationalfluiddynamics(CFD)andfluid thermalstructuralinteractionwasbetiredAnsys.
P Chandrasekhar1, Naveen Kumar2, Nagaraja S N3
Non Contact Bearings: Hydrodynamic Mechanicsbearingswerealtogetherchanceusedfor severalyearsbeforehuman,WorldHealthOrganizationwas one all told the pioneers of fluid film analysis (as well as severalcompletelytotallydifferentthings!),introducedthe thoughtofasteptoassistbuildupthehydrodynamicwedge. In 1912, blue blood prince Kingsbury discovered that for large bearings, like those accustomed support turbines, it had been impractical to make a flat enough continuous thrustsurface.
1.Introduction
The material pressure applied at intervals the bearing, in static analysis the deformation is not bearings square measure machine parts that enable parts to maneuverwithassociationoneanotherTherear2sortsof bearings, contact and non contact. Contact kind bearings havemechanicalcontactbetweenparts,thattheyembody lubricious,rolling,andflexuralbearings.Mechanicalcontact means stiff land ancient to the direction of motion ar planning to be terribly high, however wear or fatigue will limittheirNonlife.contactbearingsembodyexternallycontrolled and mechanics fluid film (liquid, air, mixed phase) and magneticbearings.thedearthofmechanicalcontactsuggests that static friction square measure attending to be eliminated, though viscous drag happens once fluids ar present; however, life square measure attending to be relating to infinite if the external power units required to managethemdonotfail.
Fig 1.2:Non contactbearing Hethusseparatedthesurfaceintoseverallytiltable regions.Theaxisoftiltwaspositionedthatthetiltingpads wouldindividualsmechanicswedgetoresistthrustawhole bunch. His company, additionally as type of his original bearings,continuestobeinbusinesstoday!thus,mechanics
Key Words: Hydrodynamic journal bearing, fluid interaction technique, CFD.
2Associate Professor, Dept. of Mechanical Engineering, Kuppam Engineering College, AP, India
bearingsaregenerallyused,e.g.,inburningengines,thanks totheirsimplicityandintenselyhighloadcapability
Hydrodynamic journal bearings and varied, in general, fluid film bearings unit generally accustomed support rotors in stylish power plants (e.g., micro GT cell hybridsystems)andcrankshaftsinautomotiveapplications (e.g.,rodbearingincombustionengines).Theirruleisbased on the interposition of a thin self controlled material material between the two opposing bearing surfaces that unitinrelativemotion.asdegreeexample,forwardthatthe relative radial clearance is one per thousandth (1/1000), sincejournaldiametersoflittleGTbearingsunitgenerallyat intervalsthevary10 20mm,filmthicknessisrelatingto10 micronsTherefore,[1]. really top of the range standards and tolerancesunitrequiredtosupplythisclassofbearings,that havetobecompelledtobecompelledtobeready madewith high accuracy processes. The comparison of experimental and numerical results has been used at intervals the at intervalstheoninstabilityofmechanicsjournalbearings.as associatedegreeexample,byconsideringallofthenonlinear terms in equations and victimization in house developed takeaglanceatrigs,theeffectofeveryjournalandbearing defectsonstabilityhasbeenstudied[2]. Alotofrecently,experimentalinvestigationshave targetedonbearingfriction.In[3],associateinnovativetake a glance at rig has been used thus on decide friction with highactivityaccuracy.Theauthorshaveadministeredwhole totally utterly totally different tests variable load and slippery speed every in mixed and full film lubrication regimes.theyhaveobtainedfinishesupinsidethetypeofa Stribeck curve whose trend is in good agreement with literaturefindings.Thestaticanddynamicperformancesof very little or no mechanics journal bearings (i.e., in laboratoryapplications)havealreadybeeninvestigatedin severalworksbysuggeststhatofeverynumericalwaysthat} withinwhichinsidewhichandRK typeexperimentaltakea glanceatrigs. For instance, T˚umaandBiloˇs [4]have studied the firmness of rotor vibrations throughout an impression by suggeststhatoffullanalysisandaRK4RotorKitdevice;they havefinishedthatjournalmotionatintervalsthebearingis dominatedbyamixofequationsofmotion,whichmaybe remarkedaslinearandnonlinearmodels.
obtained
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MeruaneandPascual[5]havefoundthatnonlinear dynamic coefficients can powerfully powerfully their stiffness and damping. they have used a CFD simulation modelinADINAandaRotorKit2000experimentalrig.
3. Theoretical Calculations: D=journaldiameter Db=bearingdiameter Min=minimumC=clearancefilmthickness hmax=maximumfilmthickness N=journalspeed L=lengthofjournal Ƞ=oilbody Vm=peripheralrateofjournal ϵ=Eccentricityrelation W=safeoperationalload ɸ=angleangle ΔT=temperaturerise Ψ=relativeclearance Analyticalcalculationiscreatedbyexploitationvogueinfo book;we'vegotabenttotendtoassembletheplanninginfo forbearing(giveninTable1)thenwe'vegotabenttotend to used totally fully completely different formulas [6] for scheming safe most pressure, safe operative load and temperaturerise. Bearingpressure General electrical industrial plant formula: Pa = half dozen.2*105* Weknow Vm=πDN/60 Vm=21.99m/s PaThen=1.74*106N/m2orone.74MPa[Averagepressure] VictorTatarinoff‟sequation: P=13.5* P=4.76MPa[safemostpressure]
2. Literature Review
T˚umaetal.[6]havedisbursedeveryexperimental and theoretical investigations to assess the influence of externalexcitationsonrotorbehaviourandstability:perthe results,theyhavenotedthatkinematicexcitation cancanamplitudesofvibrationbutnotthefirmnesslimit.
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1090 H.F.Moore‟sequationforimportantpressure: laptop= seven.23*105 Pc=3.4MPa Safeoilfilmthickness hmin=2.37*10 5*Vm0.4*A0.2 hmin=0.05067mmorfifty.67µm NowEccentricityweallknowthat hmin=Cr(1 E) ϵ=thereforeeccentricitye=2*10 4mor200µm Attitudeangle ɸ=Tan 1 ɸ= ϴmax30.50atPmax=Cos 1=1620 Safeoperationalload VictorTatarinoff‟sequationforsafeoperationalload HenceW=351.60KN Temperaturerise Thetemperatureriseofthematerialfilmisbecauseofheat generated that is to be frenzied by the material, are often QWherefoundis[Volumeoffilmthat's*(Dapairof d2)*length]per QSo,second=2.31*10 5m3/s P= 250N10826.87N/m2loadofshaftforbearingportionaswe'venotsetany loadatthestarti.e. [π/4*D2*L*density(898.9kg/m3)]=25kgapprox.Or250N ΔT==ahundredandtwenty.08967indegreeKelvin 4. Structural& Modal Analysis Of Cylindrical Journal Bearing Eccentricity-0.2 Fig4.1 : 3DModellingandLengthForEccentricity0.2 Fig 4.2: 3DModellingforLubricationForEccentricity0.2 Fig 4.3 : AssemblyofBearingandLubricationFor Eccentricity0.2 Lubricant: SAE 30 Saved from Model as .iges format
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1091 Import InletMeshedmodelmodel&outlet Mass flow rate Fig4.4: Pressure Thelubricant(SAE30)isenteringintocertainmass flowrate(0.1kg/sec)alongwithpressureof1barandalso 1200Ctemperature.Thelubricantmaychangeitsproperties duetosurfacefrictionand propertiesof the material.The maximumpressure(1.02e+7Pa)isobtainedattheentryof thejournalbearingandminimum(2.03e+4Pa)atexit. STRUCTURAL & MODAL ANALYSIS OF CYLINDRICAL JOURNAL BEARING ESEENTRICITY 0.2 SAE Material30 properties
The imported pressure is applied on the inner surface of the bearing therefore the internal stresses will develop.Themaximumstressis158.37MPaatentryofthe lubricant and therefore gradually reduces at exit of the bearing(minimumstressis3.6722MPa)
Fig4.7: Stress
Fig4.5: Imported Pressure
Above figure represents the imported pressure from CFD Simulation.Thepressureiscontactwithinnersurfaceofthe bearing.
Theimportedpressureiscontactwithinnersurface ofthebearingthentheremaygetdeformationinbearings. Themaximumdeformationis0.098692mmandminimumis 0mm
Fig4.8: Strain
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Fig4.6: Deformation
Theabovefigurerepresentsthestrain (change in length to original length). After passing the lubricant, the maximumstrainis0.001534andminimumis5.2398e 5.
The above figure represents the mode3, the frequencies develops under the pressure is 2187.8Hz and maximumdeformationduetofrequencyis28.897mmand minimumis0mm
Fig4.9: Mode1
5. Results and discussions In above graph represents that CFD Pressure for two differentlubricantsfordifferenteccentricities.Inthis,SAE30 have high pressure when compared with SAE40 oil in all Ineccentricities.higherthangraph,theCFDpressureisforeigntothestatic
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1093
The above figure represents the mode1, the frequencies develops under the pressure is 2036.7Hz and maximumdeformationduetofrequencyis31.211mmand minimumis0mm
Fig4.10: Mode2 The above figure represents the mode2, the frequencies develops under the pressure is 2037.2Hz and maximumdeformationduetofrequencyis31.177mmand minimumis0mm
Fig4.11 Mode3
Theanalysismaterial pressure applied within the bearing,in static analysisthedeformationisnotedfor2lubricantsandtotally
Thelubricantpressureappliedinsideofthebearing, The material pressure applied withinthe bearing,in static analysis the deformation is noted for 2 lubricants andtotallydifferenteccentricities.Inthis,lessdeformation isdeterminedoncethematerialisSAE40oilwereused.
International Research Journal of Engineering and Technology (IRJET) e ISSN: 2395 0056 Volume: 08 Issue: 12 | Dec 2021 www.irjet.net p ISSN: 2395 0072 © 2021, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page1094 different eccentricities. In this, less deformation is determinedoncethematerialisSAE40oilwereused.
[3]K.Sandvik,A.Lehtovaara,E.Makkonen,M.Kallio,K.Kuvaja, and V. T. Kuokkala, Development of a Test Device for the Evaluation of Journal Bearings, Tampere University of Technology,Tampere,Finland,2012.
[5]V.MeruaneandR.Pascale,“Identification ofnonlinear dynamic coefficients in plain journal bearings,” Tribology International,vol.41,no.8,pp.743 754,2008.
[1]C.A.NiccoliniMarmontDuHautChamp,F.Stefani,andP. Silvestri,“Developmentofanewtestrigfortheanalysisof hydrodynamicbearingsforrotorsofmicroGT,”E3SWebof Conferences,vol.113,p.03002,2019.
[6] J.Tu˚ma, A.Biloˇsov´a, J. ˇSimek, and R.Svoboda,“A simulationstudyoftherotorvibrationinajournalbearing,” JournalofEngineeringMechanics,vol.15,no.6,pp.461 470, 2008.
Thelubricantpressureappliedinsideofthebearing,static analysis the strain is noted for 2 lubricants and totally differenteccentricities.Inthis,lessstressisdeterminedonce thematerialisSAE40oilwereused.
[4] J.Tu˚ma and J.Biloˇs,“Fluid induced in stability of rotor systems with journal bearings,” Journal of Engineering Mechanics,vol.14,no.1 2,pp.69 80,2007.
REFERENCES:
[2]N.J.Huggins,“Hydrodynamicinstabilityinplainjournal bearings,”Ph.D.thesis,ImperialCollege,London,UK,1961.
Conclusions: Journalbearingmodelswillbedevelopedforspeed of3000rpmtostudytheinteractionbetweenthefluidand elastic behavior of the bearing. The speed is the input for CFD analysis and the temperature and pressure obtained fromtheCFDanalysiswillbetakenasinputforthermaland staticanalysis.TheobservationsarefollowedbyusingANSYS InCFD,themaximumpressure(1.02e+7pa)isobtainedfor sae30oilwheneccentricityisat2andminimumpressure (2.98e+4Pa)isobtainedforeccentricity 8forsae40oil.In Staticanalysis,themaximumDeformation(0.09869mm)is obtainedforsae30oilwheneccentricityisat2andminimum (0.0228mm)isobtainedforeccentricity 8forsae40oil. The maximum stress (106MPa) is obtained for sae30 oil when eccentricity is at 2 and minimum (19.738MPa)isobtained for eccentricity 8 for sae40 oil. The maximum strain (0.001534) is obtained for sae30 oil wheneccentricityisat2andminimum(0.00019)isobtained for eccentricity 8 forsae40oil. The frequencyofjournal bearingunderloadwasobservedasmaximumatmode3at eccentricity 8 when sae 30 oil utilized and minimum for sae40 oil. From all above observation, in this study under 3000rpmtheSAE40OILispreferred
