Condensation of Refrigerants HCFC 22, HFC 134a and HCFC 123 in a Horizontal Smooth Tube: (2nd Report, Proposals of Empirical Expressions for Local Heat Transfer Coefficient)

Abstract

The local heat transfer coefficients of refrigerants HCFC 22, HFC 134a and HCFC 123 condensing inside a horizontal smooth tube are measured in the ranges of total mass velocity of 90 to 400 kg/(m2.s) and heat flux of 3 to 33 kW/m2. Based on the turbulent liquid film theory and Nusselt's theory, an empirical equation for the heat transfer coefficient is proposed in the form of Nu=(Nuf2+ Nub2)1/2, where NuFexpresses the effect of vapor shear stress and NuBthe effect of gravity force. This equation correlates the experimental results within an error of ±20%. © 1994, The Japan Society of Mechanical Engineers. All rights reserved.