Example 37.2:Exergy Destruction During Expansion of Steam Po=100 kPa T0=25C determine (a)the exergy of the steam at the initial and the final states, Steam (b)the exergy change of the steam, P=1 MPa expands P2=200 kPa T1=300C T2=150C (c)the exergy destroyed,and State 1 State 2 Assumptions△KE=0,△PE=0 m=0.05 kg Steam P=1MPa u =2793.7kJ/kg SOLUTION (a) State 1: V1=0.25799m3kg Tab.C_A-6 T1=300℃ S1=7.1246kJ/kgK 42-2577.1kJ/kg State 2: P2 200 kPa T2=150℃ 2=0.95986m3/kg Tab.CA-6 s2=7.2810kJ/kgK Po 100 kPa 40=4@25℃=104.83kJ/kg Dead state: T0=25℃ V%=@25c=0.00103m/kg Tab.C A-4 So=@25℃=0.3672kJ/kgK 上游充通大 May2,2018 14 SHANGHAI JIAO TONG UNIVERSITYMay 2, 2018 14 Example 37.2: Exergy Destruction During Expansion of Steam m=0.05 kg Steam expands W Q determine (a) the exergy of the steam at the initial and the final states, (b) the exergy change of the steam, (c) the exergy destroyed, and Assumptions ΔKE = 0, ΔPE = 0 SOLUTION (a) Tab. C_A-6 Tab. C_A-4 Tab. C_A-6