Experimental investigation on convective heat transfer of heat sink based on paraffin/copper foam composite material

In this paper, an experimental study concerns natural convection heat transfer inside a heat sink based on a high porosity open-cell metal foam saturated with phase change material (PCM). Five heat sink samples, each with dimensions of 80 x 50 x 5 mm3, are tested: a pure paraffin sample and four Paraffin/Copper foam composite material samples with pore densities ranging from 10 PPI to 40 PPI and porosities of 96.1 % and 95.5 %. This study aims to evaluate the metal foam pore size influence on heat transfer enhancement. The results show that the buoyancy forces due to natural convection of liquid paraffin influence the melting interface during the phase change process. Adding metal foam improves heat transfer, uniformity, and accelerates the paraffin melting through the composite sample. Convection heat transfer is enhanced by approximately 2.2 times for the composite heat sink compared to the pure paraffin heat sink. The obtained Nusselt number shows that conduction dominates heat transfer in the paraffin/Cu foam composite heat sink compared to the other heat sinks. Furthermore, the Nusselt number decreases as pore density increases. Finally, this study proposes Nusselt number correlations, one based on pore diameter and the other on fiber diameter.