Chapter 13 - Thermal management and heat transfer

Abstract

The cellular metal is envisaged as a system that transfers heat from a hot surface into a fluid. The thermal conductivities of metal foams are at least an order of magnitude greater than their non-metallic counterparts, so they are generally not suited for simple thermal insulation though they can provide some fire protection. The thermal conductivities of closed-cell foams are; however, lower than those of the fully dense parent metal by a factor of between 8 and 30, offering a degree of fire protection. Open-cell metal foams can be used to enhance heat transfer in applications such as heat exchangers for airborne equipment, compact heat sinks for power electronics, heat shields, air-cooled condenser towers, and regenerators. This chapter summarizes the heat-transfer characteristics of open-cell metal foams. Open-cell foams having different morphology are expected to have different coefficients. As the heat transfer coefficient increases, the pressure drops across the medium. The latter can sometimes be a limiting factor in application because of the limitations on the available pumping power.