Determine the maximum cycle temperature and the plant efficiency. A gas turbine unit takes in air at 17 C and 101 kPa and the pressure ratio is 8 to 1. The compressor is driven by the H.P. turbine and the L.P. turbine drives a separate power shaft. The isentropic efficiencies of the compressor and H.P. and L.P. turbines are 0.8, 0.85 and 0.83 respectively. An automobile company considers the design of a gas turbine engine to drive a motor car.
Combustion takes place between the compressor and the first stage turbine.
The free turbine, which has no mechanical connection with the first stage turbine, drives the road wheels of the car through reduction gearing. Use g and c p for air throughout. Neglecting all losses, and assuming a combustion efficiency of 100 per cent, calculate the net power output and the specific fuel consumption under conditions of maximum air flow rate. If the isentropic efficiency for the compression and expansion process is 0.87, calculate the overall efficiency, the net specific work, the fuel-air ratio, and the specific fuel consumption.