In: Mechanical Engineering
Prob.1) Consider a combined gas and steam power plant that has a
net power output of 450 MW. The pressure ratio of the gas turbine
cycle is 14. Air enters the compressor at 300 K and the turbine at
1 400 K. The combustion gases leaving the gas turbine are used to
heat the steam to 8 MPa. up to 400 ° C in a heat exchanger. The
combustion gases exit the heat exchanger at 460 K. An open
feedwater heater is incorporated into the steam cycle operating at
a pressure of 0.6 MPa. The condenser pressure is 20 kPa. Assuming
that all compression and expansion processes are isentropic, graph
the physical and T-S diagrams and determine:
a) the ratio of the mass air and steam flows,
b) the required rate of heat input into the combustion chamber and
c) the thermal efficiency of the combined cycle.