Heat transfer performance of flat micro-heat pipe with sintered multi-size copper powder wick

Abstract

The heat flux rises dramatically as electronic circuits become more integrated. Flat micro-heat pipe (FMHP) is a popular device for high heat flux management. A novel sintered multi-size copper powder wick (SMW) is designed in this paper. The evaporator and condenser section of the SMW is a double-layer structure with two copper powder diameters. The adiabatic section is a single-layer structure. Copper powder sintering is a compelling method to achieve graded pore size design. SMW and six sintered single-size copper powder wicks (SSWs) are prepared by vacuum sintering of copper powder. The capillary pressure of wicks and heat transfer characteristics of FMHPs are experimentally investigated. The results show that the liquid transfer time of the SMW is shortened 16.59% compared to that of the SSW. The dynamic response time constant of the SMW FMHP is decreased by 0.9 s, and the overall thermal resistance is reduced by 14.22%. The heat pipe made in this study is more agreeable to heat dissipation and is of importance for thermal management in power devices.