A gas turbine is used to drive an electric generator. It consists of two stage compressors...

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A gas turbine is used to drive an electric generator. It consists of two stage compressors with an intercooler between stages, two combustion chambers, two stage turbines and a heat exchanger. The H.P turbine drives the H.P compressor, and the L.P turbine drives the L.P compressor and the alternator. The gas from the L.P turbine passes through the heat exchanger, which transfers heat to the air leaving the H.P compressor. The reheat combustion chamber between turbine stages raises the gas temperature to 600°C, which is also the gas temperature at entry to the H.P turbine. The overall pressure ratio is 10/1; each compressor having the same pressure ratio, and the air temperature at entry to the first stage compressor is 20ºC. Assuming isentropic efficiencies of 0.8 for both compressor stages, and 0.85 for both turbine stages, and that 2% of the work of each turbine is used in overcoming friction, calculate the power output in kW for a mass flow rate of 115 kg/s. The heat exchanger thermal ratio is 0.7, and inter-cooling is complete between compressor stages. Neglect all losses in pressure, and assume that velocity changes are negligibly small. Calculate also the overall thermal efficiency of the plant. For air, take cp = 1.005 kJ/kg.K and y = 1.4 and for gas, take cp = 1.150 kJ/kg.K and y = 1.333. A gas turbine is used to drive an electric generator. It consists of two stage compressors with an intercooler between stages, two combustion chambers, two stage turbines and a heat exchanger. The H.P turbine drives the H.P compressor, and the L.P turbine drives the L.P compressor and the alternator. The gas from the L.P turbine passes through the heat exchanger, which transfers heat to the air leaving the H.P compressor. The reheat combustion chamber between turbine stages raises the gas temperature to 600°C, which is also the gas temperature at entry to the H.P turbine. The overall pressure ratio is 10/1; each compressor having the same pressure ratio, and the air temperature at entry to the first stage compressor is 20ºC. Assuming isentropic efficiencies of 0.8 for both compressor stages, and 0.85 for both turbine stages, and that 2% of the work of each turbine is used in overcoming friction, calculate the power output in kW for a mass flow rate of 115 kg/s. The heat exchanger thermal ratio is 0.7, and inter-cooling is complete between compressor stages. Neglect all losses in pressure, and assume that velocity changes are negligibly small. Calculate also the overall thermal efficiency of the plant. For air, take cp = 1.005 kJ/kg.K and y = 1.4 and for gas, take cp = 1.150 kJ/kg.K and y = 1.333.

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1 Given Mass flow rate 115 kgs Overall pressure ratio 10 Each compressor pressure ratio 10 31622 HP ... View the full answer