Chapter 7, Problem 7.86P

.......A gas turbine power plant is operated between 1.5 bar and 15 bar with minimum and maximum cycle temperatures of 25 C and 1420 C, respectively. Neglect the mass of the fuel.   Determine the following: Work of the compressor in kJ/kg (2 decimal places) = Work of the gas turbine in kJ/kg (2 decimal places) = Heat added in the combustion chamber in kJ/kg (2 decimal places) = Net Work in kJ/kg (2 decimal places) = Thermal Efficiency in % (1 decimal place only) =

Water is the working fluid in a reheat-regenerative Rankine cycle with one closed feedwater heater and one open feedwater heater. Steam enters the turbine at 1400 lbf/in.² and 1100°F and expands to 500 lbf/in.2, where some of the steam is extracted and diverted to the closed feedwater heater. Condensate exiting the closed feedwater heater as saturated liquid at 500 lbf/in.² undergoes a throttling process to 120 lbf/in.² as it passes through a trap into the open feedwater heater. The feedwater leaves the closed feedwater heater at 1400 lbf/in.² and a temperature equal to the saturation temperature at 500 lbf/in.² The remaining steam is reheated to 1000°F before entering the second-stage turbine, where it expands to 120 lbf/in.² Some of the steam is extracted and diverted to the open feedwater heater operating at 120 lbf/in.2 Saturated liquid exits the open feedwater heater at 120 lbf/in.² The remaining steam expands through the third-stage turbine to the condenser pressure of 2 lbf/in.²…

An open feedwater heater is a direct-contact heat exchanger used in vapor power plants. Shown in the figure below are operating data for an open feedwater heater with H2O as the working fluid operating at steady state, where T1 = 41 °C.   Ignoring stray heat transfer from the outside of the heat exchanger to its surroundings and kinetic and potential energy effects, determine the rate of entropy production, in kW/K.