A Correlation for Forced Convective Boiling Heat Transfer of Single-Component Refrigerants in a Horizontal Smooth Tube

Abstract

An experimental study is reported on convective boiling heat transfer for HFC134a, HCFC22, CFC114 and CFC12 inside a horizontal smooth tube. The test evaporator is of the double-tube type in which the heating water flows in the outer annulus, and the local heat transfer coefficients are measured for both counter and parallel flow. Based on the supposition of Chen that the total heat flux q is represented as the sum of forced convective contribution qcv and nucleate boiling contribution qnb, a general correlation is developed for the data in the annular flow regime. The mean deviation between the calculated and measured heat transfer coefficients is 12.2% for the present experimental data and 9.5% for available data collected from previous research. According to the proposed correlation, nucleate boiling is not suppressed even in the high-quality region in the case of counter flow, while two-phase forced convection has been recognized as predominant in the high-quality-region with uniform heat flux conditions. © 1992, The Japan Society of Mechanical Engineers. All rights reserved.