A cylinder contains ethylene, C2H4 , at 222.6 lbf/in.2 , 8 F. It is now compressed isothermally in a reversible process to 742 lbf/in.2 . Find the specific work and heat transfer.
A cylinder contains ethylene, C2H4 , at 222.6 lbf/in.2 , 8 F. It is now compressed isothermally in a reversible process to 742 lbf/in.2 . Find the specific work and heat transfer.
Ethylene C2H4,R=55.07 ft lbf/lbm R=0.07078 Btu/lbm R
State 1: P1=222.6 lbf/in.2,T2=T1=8 F=467.7 R
State 2: P2=742 lbf/in.2
Tr2=Tr1=508.3467.7=0.920;Pr1=731222.6=0.305From D.1, D.2 and D.3: Z1=0.85, (RTCh∗−h)1=0.40
(h1∗−h1)=0.07078×508.3×0.40=14.4 Btu/lbm(s1∗−s1)=0.07078×0.30 □□=0.0212 Btu/lbm R
Pr2=731742=1.015 (comp. liquid)
From D.1, D.2 and D.3: Z2=0.17
(h2∗−h2)=0.07078×508.3×4.0=143.9(s2∗−s2)=0.07078×3.6=0.2548(h2∗−h1∗)=0(s2∗−s1∗)=0−0.07078ln222.6742=−0.08521q2=T(s2−s1)=467.7(−0.2548−0.0852+0.0212)=–149.1 Btu/lbm(h2−h1)=−143.9+0+14.4=−129.5
(u2−u1)=(h2−h1)−RT(Z2−Z1)=−129.5−0.07078×467.7(0.17−0.85)=−107.0
1w2=1q2−(u2−u1)=−149.1+107.0=−42.1 Btu/lbm