761 the isentropic efficiency of this turbine is

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Unformatted text preview: saturated mixture since sf s2s sg. Thus we need to find the quality at state 2s first: x2s s2s sf sfg 6.9212 1.0910 6.5029 0.897 and h2s hf x2s hfg 340.49 0.897 (2305.4) 2407.4 kJ/kg By substituting these enthalpy values into Eq. 7–61, the isentropic efficiency of this turbine is determined to be hT h1 h1 h2a h2s 3230.9 3230.9 2682.5 2407.4 0.666, or 66.6% (b) The mass flow rate of steam through this turbine is determined from the energy balance for steady-flow systems: · E in · m h1 · Wa, out 1000 kJ/s 2 MW 1 MW · m · E out · · Wa, out m h2a · (h m 1 h2a) · m (3230.9 3.65 kg/s 2682.5) kJ/kg cen54261_ch07.qxd 11/18/03 9:57 AM Page 315 315 CHAPTER 7 Isentropic Efficiencies of Compressors and Pumps The isentropic efficiency of a compressor is defined as the ratio of the work input required to raise the pressure of a gas to a specified value in an isentropic manner to the actual work input: hC Isentropic compressor work Actual compressor work ws wa (7–62) Notice that the isentropic compressor efficiency is defined with the isentropic work input in the numerator instead of in t...
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