A heat engine operates on the Rankine cycle, with saturated steam at T = 350°C leaving the boiler, a condenser operating at T = 100°C, and a turbine efficiency of 80%.

A. Find the liquid fraction leaving the turbine.

B. Find the overall efficiency of the heat engine.

C. A superheater is inserted into the cycle after the boiler, which increases the steam temperature to 450°C without changing its pressure. All other specifications remain the same. Find the liquid fraction leaving the turbine and the overall efficiency of the cycle, and compare to the answers from A and B.

D. A heat engine operates with the same boiler, pump, and condenser specifications used in parts A and B (no superheater). Instead of a single turbine, there are two turbines, each with 80% efficiency. The steam leaving the first turbine has P = 3 bar, is sent to a heat exchanger in which its temperature is increased to 200°C, and then continues to the second turbine. Find the liquid fractions in both turbine effluent streams and the overall efficiency of the heat engine, and compare to the answers in A, B, and C.