Vapor chamber with two-layer liquid supply evaporator wick for high-heat-flux devices

Abstract

Modern electronic devices with high heat flux increasingly exceed the capability of thermal management method. Two-phase thermal dissipation devices such as vapor chambers offer effective method for high heat flux cooling. Various new structural designs of vapor chambers are used as effective thermal control methods for high heat flux devices. However, the optimization criteria for the capillary wick structures are different. The combinations between the structural surface parameters and pore size of the capillary wick are different, while their influence on the heat transfer performance need to be studied. In this work, it is reported that the fabrication and thermal performance of vapor chambers with multi-layer sintered wicks and multi-artery wick design for liquid supply. We numerically and experimentally characterize the two types of sintered multi-artery wick for replenishing liquid and escaping vapor effectively with high heat flux. Three kinds of combinations of different copper particle sizes were applied to the sintered wicks in order to balance the liquid collecting rate and flow resistance. The copper particles of large particle size (60 μm/100 μm/150 μm) in the upper layer wick and copper particles of small particle size (30 μm/50 μm/100 μm) the lower layer wick were applied in the vapor chambers. In the present study, as an evaluation criteria for capillary wick designs, the relationship between surface porosity, surface area and critical heat flux was analyzed to obtain the experimental optimization of structural design and pore size combination as 50/100 μm. It was found that with similar multi-artery structure wicks, higher surface area porosity can effectively increase the critical heat flux of the vapor chambers. Judging from the experiment results, the minimum through-plane direction heat transfer resistance of the vapor chamber is 0.1426 K/W, the minimum in-plane direction heat transfer resistance is 0.016 K/W, while the critical heat flux of the vapor chamber is 262 W/cm2.