Effect of Elliptical Micropillar Spacing on Spray Cooling Performance

Abstract

Spray cooling is a promising technique for the thermal management of high-heat-flux power electronic devices, particularly insulated-gate bipolar transistor modules used in compact electric-drive motor control systems. However, the roles of microstructure spacing and spray operating conditions in governing heat transfer performance have not yet been fully clarified. To address this issue, a closed-loop spray cooling experimental facility was established. By varying the spacing of elliptical micropillars, the effects of spray flow rate, coolant temperature, and spray height on spray cooling heat transfer were systematically investigated. The results show that the heat transfer coefficient (HTC) increases with spray flow rate over the entire tested range. Within the tested spacing range, the highest surface HTC of [Formula: see text] was achieved at [Formula: see text] with a spacing of 1.6 mm. As the coolant temperature increased, the HTC initially increased, then remained nearly constant above 30°C. In addition, at a spray height of 17.3 mm and a spacing of 1.6 mm, the surface HTC reached [Formula: see text], demonstrating the strongest heat transfer capability of the tested surface.