Question

A cylinder containing 1 kg of ammonia has an externally loaded piston. Initially the ammonia is at 2 MPa, 180°C and is now cooled to saturated vapor at 40°C, and then further cooled to 20°C, at which point the quality is 50%. Find the total work for the process, assuming a piecewise linear variation of P versus V. 

Answer 1

State 3: (T, x) P₃ = 857 kPa, v₃ = (0.001638 + 0.14922)/2 = 0.07543 m³/kg Sum the the work as two integrals each evaluated by the area in the P-v diagram.