Thermal performance enhancement in open-pore metal foam and foam-fin heat sinks for electronics cooling

Abstract

Metal foam heat sinks can be employed for thermal management in high heat flux applications. They are generally produced by attaching metal foam to the metal substrate using heterogeneous epoxy-adhesives. This process is inefficient due to interfacial thermal contact resistance. Reducing the thermal contact resistance and minimizing the airflow resistance inside the foam enhance the thermal efficiency of the heat sink. We develop foam/foam-fin heat sinks to achieve this, wherein foam and substrate are thermally fused bonded. This paper presents an experimental study to investigate the influence of thermal contact resistance, geometrical configuration, and structural parameters such as pore density, foam height, and the number of fins on the thermal performance of novel integral foam/foam-fin heat sinks. The fused bonding method reduces the thermal contact resistance ∼ 19 times compared to the epoxy-gluing process. Consequently, the Nusselt number for the fused-bonded foam-fin heat sink increases by ∼ 30% than the epoxy-glued heat sink. Moreover, the heat transfer rate per unit mass of foam-fin heat sink is ∼ 2 times higher than the commercially available fin heat sink due to the higher specific surface area and reduced vortex formation adjacent to the foam-fins. Thus, fused-bonded foam-fin heat sinks are efficient, compact, lightweight, and easily recyclable heat exchangers. These results will be effective in designing efficient foam/foam-fin heat sinks for electronics cooling. • A novel integral foam/ foam-fin heat sink (HS) is produced via fused bonding method. • The effect of structural parameters on the thermal performance of the HS is studied. • Fused bonded HS shows ∼ 19 times lower thermal contact resistance and ∼ 30 % higher heat transfer than the epoxy-glued HS. • Foam-fin HS offers about twice the heat transfer rate per unit mass than commercially available heat sinks.