Continue Example 38.1 Steam Continue Solution: T=400C P=30 bars Maximum possible work output use useful work equation: T2=120C P2=1 bar +引装n装 +T.d Wr=mh-Is)-nh,-Ts,)-Tw→wr=(-h,)-T6-）-T☆ m For maximum work output,assume reversible processocv=0: Wrev.u9e.T=(h1-h2)-To (S1-S2)=W1-W2 =w1-T,(s-s)=5143-30K(6.9212-7468 kJ =677.98 kJ kg kg.K kg 上游充通大 May2,2018 10 SHANGHAI JIAO TONG UNIVERSITYMay 2, 2018 10 Continue Example 38.1 Continue Solution: • Maximum possible work output → use useful work equation: • For maximum work output, assume reversible process → σcv = 0: 2 use in v W m h 2    gz 2 o out in in v T s m h 2              gz o out out i T s Q            o CV i i T dE 1 T dt          CV o dV p dt  CV o dS T dt      o CV use,T 1 o 1 2 o 2 o CV T W m h T s m h T s T         . WT CV Steam T1=400oC p1=30 bars T2=120oC p2=1 bar     CV w h h T s s T use,T 1 2 o 1 2 o m               rev,use,T 1 2 o 1 2 1 2 T o 1 2 w h h T s s kJ kJ kJ w T s s 514.3 300K 6.9212 7.4668 677.98 kg kg K kg                