EXAMPLE 9-9 A Gas Turbine with Reheating and Intercooling expan . sion has an overall pressure ratio of 8. Air enters ea

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Example 9 9 A Gas Turbine With Reheating And Intercooling Expan Sion Has An Overall Pressure Ratio Of 8 Air Enters Ea 1 (157.74 KiB) Viewed 15 times

why is it in this question they square rooted the pressure ratio? When would you square root the pressure ratio and when would you not?
EXAMPLE 9-9 A Gas Turbine with Reheating and Intercooling expan . sion has an overall pressure ratio of 8. Air enters each stage of the compressor at 300 K and each stage of the turbine at 1300 K. Determine the back work ratio and the thermal efficiency of this gas-turbine cycle, assuming (a) no ideal regenerator with 100 percent effectiveness. Compare the results with those obtained in Example 9–6. regenerators and (b) an SOLUTION An ideal gas-turbine cycle with two stages of compression and two stages of expansion is considered. The back work ratio and the thermal efficiency of the cycle are to be determined for the cases of no regeneration and maximum regeneration Assumptions 1 Steady operating conditions exist. 2 The air-standard assumptions are applicable. 3 Kinetic and potential energy changes are negligible. Analysis The T-s diagram of the ideal gas-turbine cycle described is shown in Fig. 9-47. We note that the cycle involves two stages of expansion, two stages of compres- sion, and regeneration. For two-stage compression and expansion, the work input is minimized and the work output is maximized when both stages of the compressor and the turbine have the same pressure ratio. Thus, P PA = P, 2 --18=283 and --V8=283 4 = POP = P,