Sonntag, Borgnakke and van Wylen
9.65 An initially empty 0.1 m3 cannister is filled with R-12 from a line flowing saturated liquid at −5°C. This is done quickly such that the process is adiabatic. Find the final mass, liquid and vapor volumes, if any, in the cannister. Is the process reversible? Solution: C.V. Cannister filling process where: 1Q2 = 0/ ; 1W2 = 0/ ; m1 = 0/ Continuity Eq.6.15: m2 - 0/ = min ; Energy Eq.6.16: m2u2 - 0/ = minhline + 0/ + 0/ ⇒ u2 = hline 2: P2 = PL ; u2 = hL ⇒ 2 phase u2 > uf ; Table B.3.1:
u2 = uf + x2ufg
uf = 31.26 ; ufg = 137.16 ; hf = 31.45
all kJ/kg
x2 = (31.45 -31.26)/137.16 = 0.001385 ⇒ v2 = vf + x2vfg = 0.000708 + 0.001385×0.06426 = 0.000797 m3/kg ⇒ m2 = V/v2 = 125.47 kg ; mf = 125.296 kg; mg = 0.174 kg Vf = mfvf = 0.0887 m3;
Vg = mgvg = 0.0113 m3
Process is irreversible (throttling) s2 > sf
T line
line 2
s