Applying the volume averaging theory to open-cell metal foam in natural convection/radiation

Abstract

Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.

Heat sinks made out of open-cell aluminium foam are investigated numerically in natural convection. Results derived from a 2D numerical model are compared to results for in-house experiments. Different foam heights are studied. The numerical model is based on the volume averaging theory. The aluminium foam that is used has 10 pores per linear inch and a porosity of 93%. The temperature of the substrate was varied between 55°C and 95°C. The geometry used in the numerical model replicates the experimental test rig as well as possible. A discussion of the determination of the closure terms is given. If only convective heat transfer is taken into account in the numerical model, the relative differences between the numerical and experimental results are smaller than 29% for all foam heights studied. However, when the influence of radiation is included in the numerical model, it is shown that the numerical results differ less than 9% with the experimental ones. This validates the choice of closure terms used in the model and this shows that it is necessary to properly model radiative heat transfer in numerical models of open-cell aluminium foam in natural convection.