Question

Saturated water vapor at 20 psia is compressed to 60 psia in a reversible adiabatic process. Find the change in v and T. 

Answer 1

Process adiabatic: dq = 0

Process reversible: ds_gen = 0

Change in s: ds = dq/T + ds_gen = 0 + 0 = 0 thus s is constant  

T₁ = 227.96 F, v₁ = 20.091 ft³/lbm, s₁ = 1.732 Btu/lbm R at 60 psia and s = s₁ = 1.732 Btu/lbm R