Question

. Air enters the compressor of a gas turbine power plant operating on Brayton cycle at 14.5 psia and 540° R. The pressure ratio across the turbine and compressor is same, which is equal to 6. Assume that the compressor work as 0.4 times the turbine work. Take K=1.4 a) Draw the T-S diagram of the cycle. [2] b) Calculate the maximum temperature in the cycle. [3] c) Calculate the cycle efficiency

Answer 1

Solution-

Assumption-

• Kinetic and potential energies at the inlet and exit of turbine and compressor is neglected.
• Air standard , with constant C_P and C_V .
• Pressure ratio across turbine and compressor is same.
• Heat addition in combustion chamber takes place at constant pressure.

1) T S diagram for gas cycle-

1 - represent compressor inlet

3- Inlet of turbine at higher pressure and tenperature

Process 1-2- Isentropic compression

Process 3-4 Isentrpoic expansion

2) Maximum temperature of cycle using condition-

3) Cycle Efficiency-