Chapter 10 Boiling and Condensation10-80 Saturated refrigerant-134a vapor condenses on the outside of a horizontal tube maintained at a specified temperature. The rate of condensation of the refrigerant is to be determined.Assumptions1Steady operating conditions exist.2The tube is isothermal. PropertiesThe properties of refrigerant-134a at the saturation temperature of 35°C are hfg= 168.2×103J/kg and ρv= 43.41 kg/m3. The properties of liquid R-134a at the film temperature of 35 + 25)/2 = 30°C are (Table A-10), TTTfs=+()/sat2(=CW/m.0808.0CJ/kg.1448C/sm101590.0/kg/m.s10888.1kg/m11882643°=°=×==×==−−lpllllllkρμνμρAnalysisThe modified latent heat of vaporization is J/kg10178.0=C)25C(35J/kg14480.68+J/kg102.168)(68.033sat*×°−°⋅××=−+=splfgfgTTChhR-134a 35°C Condensate25°C Dtube = 3 cmLtube= 7 mThe heat transfer coefficient for condensation on a single horizontal tube is CW/m1581m)
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