Somchart Chantasiriwan posted a comment on discussion Open Discussion

DWSIM uses a wrong formula to compute adiabatic efficiency of expander. The correct formula is eta_adiabatic = (1 - rp^(eta_polytropic*(1-1/k)) / (1 - rp^(1-1/k)) where eta_adiabatic is adiabatic efficiency, eta_polytropic is polytropic efficiency, rp = pout/pin, and k = cp/cv. According to this formula, adiabatic efficiency must not be less than polytropic efficiency.