On the effective thermal conductivity of aluminum metal foams: Review and improvement of the available empirical and analytical models

Open cell metal foams are good candidates for augmenting the thermal performance of heat sinks and compact heat exchangers, with the added benefits of lighter and more compact equipments. Under this perspective, an estimation of the effective thermal conductivity of the medium is fundamental in order to properly design a metal foam heat transfer device. In this paper, a review of the empirical correlations and the theoretical models published in the literature for the prediction of the effective thermal conductivity is presented. In order to test the goodness of the illustrated models, a validation has been performed with the experimental data available in the literature for aluminum foams, for both air and water as working fluids and porosity higher than 0.89. For the models involving empirical or fitting constants, these parameters have been calibrated against the available experimental values, thus to enhance the predicting capability of the models. In addition, the mathematical formulation of some of the existing correlations has been revised and some efficient alternatives are suggested.