Consider a gas-turbine power plant whose pressure ratio is 8. The Isentropic efficiencies of the compressor and the turbine are 80%, and there is a regenerator with effectiveness 0f 70%. When the mass flow rate of air through the compressor is 40 kg/s, the turbine inlet temperature becomes 1700 K. But the turbine inlet temperature is limited to 1500 K, and thus steam injection into the combustion gases is being considered. However, to avoid the complexities associated with steam injection, it is proposed to use excess air (that is, to take in much more air than needed for complete combustion) to lower the combustion and thus turbine inlet temperature while increasing the mass flow rate and thus the power output of the turbine. evaluate the proposal, and compare the thermodynamic performance of "high air flow" (different design values) to that of a "steam injection" gas turbine power plant under the following design constrained conditions:
- The ambient air is at 100 kPa and 25oC.
- Adequate water supply is available at 20oC.
- The amount of fuel supplied to the combustion chamber remains the same.