Problem 3: A combined gas-steam power cycle consists of a simple Bryton cycle and reheat Rankine cycle. The topping cycle is the simple Brayton cycle that has a pressure ratio of 7. Air enters the compressor at 15°C at a rate of 10 kg/s and the gas turbine at 950°C. The bottoming cycle is the reheat Rankine cycle operates between the pressure limits of 6 MPa and 10 kPa. The mass flow rate of the steam is 1.15 kg/s. The exhaust gases of Brayton cycle leave the heat exchanger at 200°C. Steam leaves the high-pressure turbine at 1 MPa and saturated vapor "state 4" and is reheated to 400°C in the heat exchanger before it expands in the low pressure turbine. Steam leaves the condenser as saturated liquid. Assume isentropic pump, compressor and turbine. Also assume constant specific heat at 300K for the Bryton cycle and variable specific heat for the Rankine. Determine a) the quality of the steam leaving the low pressure turbine "state 6" b) the steam temperature at the inlet of the high-pressure turbine "state 3" c) the net power output and the thermal efficiency of the combined plant. TA 950°C 15°C 6 MPa GAS CYCLE 10 11 STEAM CYCLE Love 10 kPa 1 MPa Combustion chamber Compressor Gas turbine 10 11 Heat exchanger Steam turbine pump Condenser