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

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 μm. The corresponding mass flux is 100 and 200 kg m− 2 s− 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 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%