Naik, Sameer V. Fall 2009 1000 Solution for Special Problem 25Given:- Water executing Carnot heat engine cycle Find:- Pressure, temperature, specific volume, specific internal energy, specific enthalpy at all four states within the cycle - Heat transfer and work (kJ) for each process in the cycle - Thermal efficiency (%) of the cycle - P-v diagram System:Assumptions:- Carnot cycle executed in a closed piston-cylinder device - Negligible changes in KE and PE Basic Equation(s):QWUKEPE−= Δ+ Δ+ Δ1cycleCthermalHHWTQTη==−Solution:(a) At state 1, we have water at 40 bar and 15% quality. Using Table A-3: ()()3333311mmm1.2522100.15 0.049781.2522100.008532kgkgkgfgfvvxvv−−=+−=×+−×=()()11kJkJkJ1082.30.15 2602.31082.31310.3kgkgkgfgfuuxuu=+−=+−=()()111kJkJkJ1087.30.15 1714.11344.42kgkgkgfgfffghhxhhhx h=+−=+=+=At state 2, we have saturated vapor at 40 bar. Using Table A-3: 32m0.04978kggvv==, 2kJ2602.3kgguu==, 2kJ2801.4kgghh==Process 2-3 is adiabatic. Applying energy balance, we have: 232323qwu−= Δ
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