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Unformatted text preview: 9-38An ideal Otto cycle with air as the working fluid has a compression ratio of 9.5. The highest pressure and temperature in the cycle, the amount of heat transferred, the thermal efficiency, and the mean effective pressure are to be determined. Assumptions1The air-standard assumptions are applicable. 2Kinetic and potential energy changes are negligible. 3Air is an ideal gas with constant specific heats. PropertiesThe properties of air at room temperature are cp= 1.005 kJ/kg·K, cv= 0.718 kJ/kg·K, R= 0.287 kJ/kg·K, and k= 1.4 (Table A-2).Analysis(a) Process 1-2: isentropic compression. ( )( )( )( )kPa2338kPa100K308K757.99.5K757.99.5K3081122121112220.412112===→====-PTTPTPTPTTkvvvvvvProcess 3-4: isentropic expansion. ( )( )K1969===-0.4134439.5K800kTTvvProcess 2-3: v= constant heat addition. ( )kPa6072===→=kPa2338K757.9K19692233222333PTTPTPTPvv(b) ( )( )( )( )kg10788.6K308K/kgmkPa0.287m0.0006kPa100433111-×=⋅⋅==RTPmV( ) ( )( )( )( )kJ0.590=-⋅×=-=-=-K757.91969KkJ/kg0.718kg106.78842323inTTmcuumQv(c) Process 4-1: v= constant heat rejection....
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This note was uploaded on 01/25/2010 for the course ME 55806 taught by Professor Chen during the Spring '10 term at Berkeley.
- Spring '10
- Heat Transfer