Sample Test #3(2) solution
1-2, isothermal compression
2-3, constant pressure expansion
3-1, adiabatic expansion (isentropic)
First, establish a thermodynamic state table:
From the equation of the state
1-2, isothermal, T1=T2, P2=500 kPa
2-3, constant pressure expansion
P3=P2=500 kPa, T3=400K, v3=0.23(m3/kg)
T1=T3(P1/P3)(k-1)/k=400(1/5)0.287=252.6(K)
v1=RT1/P1=(0.287)(252.6)/100=0.725(m3/kg)