Enhanced capillary-driven thin film boiling on cost-effective gradient wire meshes for high-heat-flux applications

As high-power electronics continue to advance rapidly, the pursuit of efficient thermal management has emerged a critical challenge for their further high-performance and large-scale applications. Capillary-driven thin film boiling phase-change cooling, harnessing the high latent heat of vaporization, presents an effective strategy to efficiently dissipate waste heat and meet the escalating cooling requirements of high-heat-flux applications. In this study, a cost-effective gradient wicking structure was proposed to enhance the thermal performance of the wick by promoting bubble dynamics and optimizing the balance between capillary pressure and permeability in homogeneous wicks. The comprehensive capillary properties of the homogeneous wicks were analyzed through theoretical calculations, and the capillary-driven thin film boiling heat transfer performance of four wick samples was systematically studied experimentally. Additionally, the effects of reduced pressures on the thermal performance of the gradient wick were investigated. Notably, the gradient porous wicking structure demonstrated exceptional thermal performance, with a critical heat flux reaching as high as 202.8 W/cm(2) and a maximum heat transfer coefficient of 121.9 kW/m(2)center dot K achieved at 88.5 W/cm(2). The findings of this study offer valuable design guidelines for the wick structures utilized in phase change equipment, with potential wide-ranging applications in advanced thermal management.