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This is problem 8-13 from El-Wakil’s Powerplant Technology book – Consider a combined gas-steam turbine cycle...

This is problem 8-13 from El-Wakil’s Powerplant Technology book – Consider a combined gas-steam turbine cycle with both machines ideal. Air enters the compressor at 1 atm and 500 degree R. 200 percent theoretical air gases enter the gas turbine at 2400 degree R. The pressure ratio for both compressor and turbine is 5.624. No intercooling, reheat, or regeneration are used in the gas-turbine cycle. The turbine exhaust is used directly without supplementary firing and leaves to the stack at 1000 degree R. Steam is produced at 1000 psia and 1000 degree F. The condenser pressure is 1 psia. No feedwater heating is used and the pump work may be ignored, Draw the flow and T-s diagrams labeling points correspondingly , and calculate (a) the heat added, per pound mass of air,(b) the steam flow per pound mass of air, (c) the combined work, in Btus per pound mass of air, (d) the combined plant efficiency, and (e) the plant efficiency if the steam cycle is inoperative.

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