Performance Comparison of Various Thermal Interface Materials Used with Metal Foams

Metal foams are promising materials for electronics cooling applications due to their high surface area-to-volume ratio. Their use in electronics cooling requires excellent contact between the heated surface and the foam, which is typically achieved using a thermal interface material (TIM). However, TIMs are typically designed for metal-to-metal interfaces and are not assessed for improving heat transfer at metal foam contacts. Thus, this study aims to reveal the performance of different TIMs when used with metal foams. An experimental setup is built where a metal foam is placed inside a rectangular channel and exposed to a constant heat flux. The thermal performance of the thermal gap pad, thermal epoxy applied to the heated surface, thermal epoxy applied to the strut ends, flexible graphite, and the condition of no TIM are assessed. A comprehensive investigation of the fluid flow and heat transfer in the metal foam for these configurations is also conducted numerically using local thermal non-equilibrium porous media equations. The numerically predicted thermal characteristics are compared with measurements. It is found that using in-plane thermally conductive TIMs can enhance heat transfer by around 18% for the same flow rate and pumping power.