General Approach to Problem Solving•Sketch the process. Define your system. Label all known and unknown quantities.•Choose a model for the working substance.•Write down the mass balance equation.•Write down the energy balance equation.•Write down the entropy balance equation.•Use specialized or combined forms as needed.Controlvolumeor systemMassentering (1)Massleaving (2)QW
has intentionally blurred sections.
Sign up to view the full version.
Models of Working SubstancesSolid/liquidTable A-3Cp= Cv= CGasesPhase-changefluids(water &refrigerants)Tables A-2 to 8 & A-11 to 13Mixtures(advanced)Perfect gasPv = RTCp= constantCv= Cp– RTable A-2a for Cp.u = CvT, h = CpT.P and T are absolute.Ideal gasPv = RTCp= f(T) Table A-2b,c.Cv= Cp– RTable A-17 to 25for u and h.P and T are absolute.Real gasFigures A-15RTPvZvv)P,T(fZactualidealactualRR===cRcRPPPTTT==P and T are absolute.∫∫==T0vT0pdTCudTChThis chart was inspired by Subrata Bhattacharjee, The Expert System for Thermodynamics,