The basic layout of a combined Brayton-Rankine cycle is shown in Fig. 9.49. Air enters the isentropic compressor at 10°C and 100 kPa, with a mass flux of 30 kg/s. The pressure ratio for this compressor is 6. The exhaust gases leave the combustion chamber and enter the isentropic gas turbine at 900°C. The ideal Rankine cycle operates between 40 kPa and 4 MPa. Steam at 4 kg/s enters the isentropic steam turbine at 400°C. Assuming constant specific heats for the air, calculate:
i) The net work output of the ideal-gas turbine engine
ii) The efficiency of the ideal-gas turbine cycle
iii) The heat exchanged in the heat exchanger
iv) The work output of the ideal Rankine cycle
v) The efficiency of the ideal Rankine cycle
vi) The combined cycle efficiency
Figure 9.49

Transcribed Image Text:

Combustór 4600 kPa 1200 C GT Gas l turbine Compressor 100 kPa Air 10C O Heat exchanger 100 kPa 400 с 24 MPa WST Steam turbine Pump 40 kPa Condenser out