Lightweight compact heat exchangers with open-cell metal foams

With rapid progress in materials processing, a number of low cost porous materials have beenproduced and employed as the core parts of lightweight structures due to their distinctivemechanical, thermal, electrical and acoustical properties. Highly porous cellular metallicfoams with open cells provide all of these attributes and are under serious consideration for avariety of engineering applications. With open cells, the pores of the metal foam areinterconnected, providing three-dimensional irregular and tortuous flow paths andsubstantially large extended heat transfer surfaces. These topological advantages of open-cellmetal foams over conventional heat dissipation media can be tailored to make lightweightcompact heat exchangers. Thus far, the fundamental flow and thermal transport behaviors ofopen-cell metal foam heat exchangers have been characterized based on both micro- andmacro-structural properties under various heat transfer configurations. This chapter aims tofirstly review the recent progress and then present some new results on the fundamentalresearch and applications regarding the thermo-fluidic properties of open-cell metal foam heatexchangers. In this work, the thermo-physical aspects of open-cell metal foams as heatexchangers are grouped into three different categorizes depending on the cooling strategyused: (i) forced liquid/air convection in open-cell metal foam channels/tubes, (ii) impingingsingle circular and annular jets on open-cell metal foams, and iii) impinging axial fan flowthat swirls periodically on open-cell metal foams.