Water is the working fluid in a regenerative Rankine cycle with one closed feedwater heater and one open feedwater heate

[answerhappygod]

Water Is The Working Fluid In A Regenerative Rankine Cycle With One Closed Feedwater Heater And One Open Feedwater Heate 1 (142.59 KiB) Viewed 29 times

Water is the working fluid in a regenerative Rankine cycle with one closed feedwater heater and one open feedwater heater. Steam enters the turbine at 1400 lbf/in.? and 950°F and expands to 400 lbf/in.?, where part of the steam is extracted and diverted into the closed feedwater heater. Condensate exiting the closed feedwater heater as saturated liquid at 400 lbf/in.? is trapped into the open feedwater heater operating at 140 lbf/in.? The feedwater leaves the closed feedwater heater at 1400 lbf/in.? and a temperature equal to the saturation temperature at 400 lbf/in.? The remaining steam expands through the second-stage turbine to 140 lbf/in.2, where some of the steam is extracted and diverted to the open feedwater heater. Saturated liquid exits the open feedwater heater at 140 lbf/in.? The remaining steam expands through the third-stage turbine to the condenser pressure of 1.5 lbf/in.? The turbine stages operate adiabatically with isentropic efficiencies of 88%, and the pumps each operate adiabatically with isentropic efficiencies of 82%. Flow through the condenser, closed feedwater heater, open feedwater heater, and steam generator is at constant pressure. The net power output of the cycle is 5 x 108 Btu/h. Determine for the cycle: a) the mass fraction of steam diverted to the closed heater after the first turbine stage. b) the mass fraction of steam diverted to the open heater after the second turbine stage. c) the back work ratio. d) the mass flow rate of steam entering the first stage of the turbine, in lbm/h. e) the rate of heat transfer, in Btu/lbm, to the working fluid passing through the steam generator. f) the thermal efficiency.