Modeling of gas flow through isotropic metallic foams

Because of their high porosity and especially their very high surface area, metal foams find application in various engineering processes such as gas distributors in fuel cells. Thus, there is a need for the prediction of the pressure drops for given fluid flow rates. In this paper, we present an improvement of the hydraulic model proposed by Du Plessis et al. (1994) adapted to isotropic metallic foam structures in which stagnant zones could exist. Experimental results for airflow through two different metallic foam structures (stainless steel and aluminum foams) are analyzed by application of the theoretical model and the results interpreted. The foams differ because of larger localized solid chunks at the strand interconnections and covered faces of some pores in the stainless steel foams than in aluminum foams. The results show that the submodel, in which there are no stagnant zones, allows good predictions of pressure drop without any fitting parameters for the aluminum foam, knowing the mean strand diameter and the porosity of the foam. In the case of stainless steel foam, results suggest that a combined model of the doubly staggered model and the granular model (Du Plessis and Masliyah, 1991) must be developed.