Performance improvement of loop heat pipe by micro-pin-fins/powders composite surface

Abstract

The loop heat pipe incorporating flow boiling (LHPFB) achieves much higher heat flux than conventional loop heat pipes (LHPs). However, the operating temperature is too high for the thermal management of electronic devices. In this study, various surfaces are fabricated on the boiling chamber baseplate of the LHPFB to reduce the junction temperature. The micro-pin-fins/powders composite surface has the best performance with the junction temperature reduced by 9.7℃, but it can hardly increase the heat transfer limit. When the coolant temperature is 25℃ and the evaporator thermal load is 200 W, the LHPFB with composite surface achieves a heat transfer limit of 500 W with the corresponding heat flux of 103.3 W·cm−2, and the operating temperature is 90.4℃. A theoretical model for heat transfer limit is proposed, based on which several methods to further improve the thermal performance are put forward. Compared with the conventional LHPs, the LHPFB with composite surface has the advantages of high heat transfer limit and low operating temperature, and therefore is a promising candidate for the thermal management of high-heat-flux electronic devices.