In the given simple cycle (Brayton) gas turbine plant shown in the diagram, the power output of the turbine is 147 MW. The temperature ratio in the plant is 5.278, and the pressure ratio is 13.6. There is a pressure drop of 0.06 bar from the compressor outlet to the turbine inlet. The changes in state in the compressor and turbines are considered adiabatic. Based on this information:
a) Calculate the total heat input to the Brayton cycle (20 points).
b) Calculate the thermal efficiency of the Brayton cycle (10 points).
To utilize the waste heat rejected from the turbine, you are required to design a combined plant with a steam turbine cycle (Rankine) without a regenerator. In the design, an effectiveness value of 0.85 will be used for a heat exchanger to recover heat from the waste energy. The isentropic efficiency of the steam turbine is 85%, the condenser pressure is at 92% vacuum, the pump isentropic efficiency is 80%, and the pump discharge pressure is assumed to be the same as the steam turbine inlet pressure.
a) Draw the schematic diagram and T-s diagram of the combined cycle (10 points).
b) Determine the total net power output of the combined cycle in MW (30 points).
c) Calculate the thermal efficiency of the combined cycle (30 points).
Note:
The cycle assumes standard air.
If necessary, make reasonable assumptions for the calculations and specify the assumptions you made within the project.
The working fluid in the Brayton cycle is assumed to be air. Also, assume no increase in mass flow rate due to fuel input.
The lower cycle of the plant will be composed of basic Rankine cycle components.
You are expected to use the EES program, but it is not mandatory.
