Aluminum foams have been frequently proposed as suitable for applications in fluid flow, [1] including as heat exchangers. In laboratory investigation, such foams have been shown to have great potential in convective heat transfer, [2] where thermally induced density differences generate fluid flow, and in forced convection, where an external force causes the fluid to move. [3][4][5] Here forced convection heat exchangers are considered. In these components, the foam is connected to a solid part, and fluid is flowed through the foam. Depending on which of the fluid and the solid are higher in temperature, heat will flow from solid to fluid or vice versa, with the foam acting to mediate the heat transfer behavior. There are two key properties that are important in heat exchanger design; the heat transfer coefficient (the amount of heat energy transferred), and the pressure drop across the heat exchanger (how hard it is to get the fluid to pass through the foam).In tests on the use of metal foams for this type of application, it is found that metal foams outperform similar dense metal configurations (e.g., refs. [3,5] ). In recent investigations of the heat transfer behavior of foams, it is found that, for the range of foams tested (with a generally high level of porosity), the best performance is obtained with higher volume fraction solid, [4] but the range of foam types that have been thoroughly investigated remains low.To increase this range we report here investigations of the heat transfer coefficient, benchmarked with a commercial aluminum foam, Duocel, and on aluminum foams produced by the replication process. In the latter case, foams with regions of different pore size are created, and the effect of this on the heat transfer is investigated.

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