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 440 mu m. The corresponding mass flux is 100 and 200 kg m(-2) S-1, respectively. The inclinations include -90, -45, 0, 45, and 90 degrees 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 25 kW m(-2). Yet this is applicable for G = 100 or 200 kg m(-2) s(-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 40 kW m(-2), it appears that nucleate boiling may impose appreciable effect on the heat transfer mechanism. For G = 100 kg m(-2) s(-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 = 200 kg m(-2) s (-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% (C) 2015 Elsevier Ltd. All rights reserved.