プレートフィン熱交換器内の冷媒の凝縮および蒸発伝熱特性

概要

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An experimental study of condensation and evaporation of pure and mixed refrigerants in a plate fin heat exchanger was carried out. Pure refrigerants of HCFC22 and HFC134a and binary refrigerant mixtures of HCFC22/CFC114 were tested in the ranges of heat flux from 10 to 65 [kW/m^2] and of mass velocity from 50 to 100 [kg/(m^2・s)]. It is clarified that the heat transfer characteristics of condensation and evaporation in the experimental range are not affected by shear stress, but controlled by gravity force. The experimental values of local Nusselt number of both condensation and evaporation of pure refrigerants are ten times higher than the values predicted from a semi-empirical equation for free convection condensation heat transfer of pure refrigerant inside a vertical tube, while the experimental values of refrigerant mixtures are lower than the predicted values and the difference depends on molar fraction.
九州大学の論文
1994-11-10