A gas-turbine plant operates on the regenerative Brayton cycle, the schematic diagram of which is shown in Fig. Q 1, with two stages of reheating and two-stages of intercooling between the pres- sure limits of100 and 1200 kPa. The

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A gas-turbine plant operates on the regenerative Brayton cycle, the schematic diagram of which is shown in Fig. Q 1, with two stages of reheating and two-stages of intercooling between the pres- sure limits of100 and 1200 kPa. The working fluid is air. The air enters the first and the second stages of the compressor at 300 K and 350 K , respectively, and the first and the second stages of the turbine at 1400 K and 1300 K, respectively. Assuming both the compressor and the turbine have an isentropic efficiency of 80%. The regenerator has an effectiveness of Egen = 75%. Assume var iable specific heats (i.e., use the concept of relative pressures) and the intermediate pressures of intercooling and reheating is the square root of the product of inlet and exit pressures for inter- cooling and reheating. Make other the necessary assumptions and determine (a) the back work ratio, B, and the net work output, wnet (b) the thermal efficiency (that is the first-law efficiency, 7, ) and (c) the relative efficiency (that is the second-law efficiency, 71). Draw the correct T-s diagram for this cycle with labelled property values. R = 287 J/(kg K). air 10 Regenerator Reheat Combustor Combustor Compressor Stage 1 Compressor Stage 2 Turbine 1 Turbine 2 2 Intercooler Fig. Q 1

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