Heat removal by aluminum-foam heat sinks in a multi-air jet impingement

The present experiment investigates the effects of the pore density of aluminum foam heat sinks, the jet velocity, the jet-to-jet spacing and the nozzle plate-to-heated surface separation distance in a 3/spl times/3 square multi-jet impinging array on the averaged Nusselt number. Thermal performances of 10, 20, and 40 PPI (pores per inch) aluminum foam heat sinks and a conventional plate-fin heat sink are evaluated in terms of the averaged Nusselt number. The jet Reynolds number is varied in the range of Re=1000-13650. The highly permeable 10 PPI aluminum foam heat sink shows higher Nusselt numbers than the 20 and 40PPI aluminum foam heat sinks both in the multi-jet and the single jet impingements. For the single jet impingement, the aluminum foam heat sinks display 8-33% higher thermal performance compared to a conventional plate-fin heat sink while the enhancement is 2-29% for the multi-jet impingement. The multi-jet impingement shows higher heat transfer enhancement than the single jet impingement for high jet Reynolds number and smaller jet-to-jet spacing in the present experiment.