Fabrication and enhanced thermal performance of a self-rewetting wick of silicon-based loop heat pipe

Abstract

The improvement of chip integration has led to increased heat flux, making heat dissipation in confined spaces increasingly challenging. Silicon-based loop heat pipes (sLHPs) offer a simple, reliable, and easily integrated thermal management solution. Still, problems like dry-out, limited heat exchange area, and flow instability hinder further heat transfer improvements of sLHP. Therefore, a novel composite MCC wick (Microchannel-micropillar Composite Cell arrays wick) incorporating microchannels into the micropillar arrays has been designed and experimentally studied in this work. The results indicate that micropillar arrays provide fluid flow freedom and a high heat exchange area, benefiting the efficient evaporation of the working fluid. The microchannels enhance fluid flow stability by providing continuous adhesion, promoting the directional supplement of working fluid. Moreover, liquid-replenishment microchannels have been introduced to the proposed MCC wick, enabling self-rewetting of the wick and enhance liquid film evaporation. The highest effective thermal conductivity of the sLHP reaches 856 W/(m·K) after structural optimization, which is significantly higher than that of other sLHPs. This work is expected to provide valuable insights for the optimal design of LHPs and chip heat dissipation.