Thermal characterization of a heat exchanger equipped with a combined material of phase change material and metallic foams

The present work is an experimental and numerical study on a heat exchanger equipped with a composite material for electronic thermal management application. The composite material is composed of paraffin wax incorporated in metal foams. Five samples with dimension of (80 x 50 x 5) mm(3) are tested: pure paraffin, paraffin/nickel foam composite with a porosity of 97.2%, and a pore density of 20 PPI and paraffin/copper foam composites with a porosity of 96.1% and pore densities of 10 PPI, 20 PPI, and 40PPI. The main results give the effects of the porous matrix morphology on the thermal performance of the heat exchanger, as the storage capacity and the accumulated power. Therefore, the obtained results show that the metal foam insert improves the heat diffusion 4 times compared to the pure PCM. In contrast, the storage capacity of the heat exchanger (SCHE) decreases to 13%. This decrease is inversely proportional to the pore density. A numerical analysis is used to deduce the effective thermal conductivity of the samples. Based on the finite element method (FEM) and the two energy equations, the numerical study is carried out with the COMSOL Multiphysics software. The numerical results show that the composite material insert improves significantly the thermal diffusivity and effusivity up to 34.5 times and 6 times, respectively. (C) 2019 Elsevier Ltd. All rights reserved.