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Unformatted text preview: Calculation of H involving latent heat: = H mHlatent H latent : latent heat of phase change (J/Kg) Thermal energy balance (negligible work): + = + Qi MiHi Qe MeHe If well insulated at system boundary: = = Qi Qe 0 Energy balance for an open system For a steady flow system, energy of a process stream includes: Internal E = E i Potential E PE = mgz Kinetic E KE =mu 2 /2 Flow work (Pressure energy) E = PV Total energy: = + + + E Ei EKE EPE PV i.e. = + + + E Ei mu22 mgz PV Based on 1 st law of thermodynamics: = -=-E Q W Eout Ein-= , + + +-( , + + + ) Q W Ei 2 m2u22 mgz2 P2V2 Ei 1 m2u12 mgz1 P1V1 When expressed on a basis of unit mass: = + +-+ + + ,-, + Qm u222 gz2 P22 u122 gz1 P11 Ei 2' Ei 1' Wm...
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- Fall '11