An experimental study of inclination on the boiling heat transfer characteristics of a micro-channel heat sink using HFE-7100

Abstract

In this study, the effect of inclination on the two-phase convective boiling heat transfer characteristics of HFE-7100 is investigated experimentally in a multiport micro-channel having a hydraulic diameter of 440μm. The corresponding mass flux is 100 and 200kgm−2s−1, respectively. The inclinations include −90, −45, 0, 45, and 90° with respect to the horizon. Test results show that normally the heat transfer coefficient for upward arrangements is superior to those of downward arrangement at a supplied heat flux of 25kWm−2. Yet this is applicable for G=100 or 200kgm−2s−1. The heat transfer coefficients increase with the vapor quality and peak again at a vapor quality of 0.6, suggesting a controlled mechanism of convective boiling. With the rise of heat flux to 40kWm−2, it appears that nucleate boiling may impose appreciable effect on the heat transfer mechanism. For G=100kgm−2s−1, the heat transfer coefficients for all arrangements are insensitive to change of vapor quality (x<0.6), implicating that nucleate boiling is in control. Analogous results prevail for G=200kgm−2s−1. Six heat transfer correlations are used to predict experimental data in different orientation. It appears that the Kandlikar correlation shows the best predictive ability against the present data with an overall mean deviation of 29.04%