Consider a regenerative vapor power cycle with two feedwater heaters, a closed one and an open one. Steam enters the first turbine stage at 80 bar, 480°C, and expands to 20 bar. Some steam is extracted at 20 bar and fed to the closed feedwater heater. The remainder
expands through the second turbine stage to 3 bar, where an additional amount is extracted and fed into the open feedwater heater, which operates at 3 bar. The steam expanding through the third turbine stage exits at the condenser pressure of 0.08 bar. Feedwater leaves the closed heater at 205°C, 80 bar, and condensate exiting as saturated liquid at 20 bar is trapped (throttled) into the open heater. Saturated liquid at 3 bar leaves the open feedwater heater. The net power output of the cycle is 100MW. If the turbine stages and pumps are isentropic, draw cycle on a T-S diagram and determine
a) The thermal efficiency of the cycle
b) The mass flow rate of steam entering the first turbine in kg/h