Metal foam has large specific surface area and good capacity of thermal conductivity. This paper aims to explore and examine the heat-transfer characteristics of copper foam heat sinks with different porosity and pore density. Some important factors on pressure drop and heat transfer characteristics, such as pore porosity, pore density and flow velocity, are investigated in detail. These results means that the flow resistance about samples depends on both factors: porosity and PPI.

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... the pore density of porous-copper sample is of great significance on flow resistance. For the same pore density and flow rate, the more porosity, the more pressure drop. Compared with empty channel, the metal foam could enhance the heat transfer dramatically but pay the price for pumping consumption. Generally, the metal foam samples with 45 PPI had slightly lower thermal resistances at the same flow rates but less pressure drops than those with 90 PPI. It means that the samples with 45 PPI could possess better overall performance between pressure drop and heat transfer characteristics. With lowest thermal resistance but highest flow resistance, the case with the porosity 0.7 and 90PPI also shows relatively good overall performances. The maximum Nusselt number for the copper foam was almost thirteen times larger than that of empty channel, which is consistence with previous conclusion in reference.