Analytical and numerical prediction of heat transfer and pressure drop in open-cell metal foams

Abstract

Enhanced cooling methods are needed for advanced power systems. A promising method is using an open-cell metal foam to improve the heat transfer rates. However, the pressure drop induced by the metal foams is relatively higher and thus becomes a critical issue in engineering applications. The focus of this research is the modeling and simulation of heat transfer enhancement and corresponding pressure drop. A simplified analytical model based on diamond-shaped unit cells has been developed to predict the heat transfer capability of a foamed channel. The heat transfer rates predicted by the analytical model have been compared with available experimental data from other researchers and favorable agreements have been obtained. To evaluate the pressure drop in metal foams, a unit-cell CFD model was built using software package Fluent. The model is based on a structure of sphere-centered open-cell tetrakaidecahedron, which is very similar to the actual microstructure of an aluminum metal foam. Flow patterns and grid independence are investigated and simulation results are shown to agree well with experimental data.