FLOW BOILING OF R-141b INSIDE PLAIN AND MICROFIN TUBES

摘要

The power and micro-electronics industries demand heat transfer solutions with a high temperature, low temperature gradient and high heat flux. In this regard, solutions using a high boiling temperature refrigerant, whose temperature is higher than the ambient temperature, are promising. In this paper, the heat transfer coefficients for flow boiling of HCFC R-141b inside plain and microfin tubes, at 1.47 bar and 43 deg C, are presented. The experimental data are obtained for mass velocity, vapor quality and heat flux in the ranges of 100 and 250 kg/m~(2)s, 0percent and 80percent and 4.7 kW/m~(2) and 14.2 kW/m~(2), respectively. The strong dependence on heat flux and the positive monotonic nature of the heat transfer coefficient as a function of the vapor quality shows a particular behavior for the partial nucleate boiling and convective boiling regimes. The results are discussed and compared with correlations and models from the literature.