Lord Kelvin and Weaire–Phelan Foam Models: Heat Transfer and Pressure Drop

Abstract

The knowledge of thermal transport characteristics is of primary importance in the application of foams. The thermal characteristics of a foam heavily depend on its microstructure and, therefore, have to be investigated at a pore level. However, this analysis is a challenging task, because of the complex geometry of a foam. The use of foam models is a promising tool in their study. The Kelvin and the Weaire–Phelan foam models, among the most representative practical foam models, are used in this paper to numerically investigate heat transfer and pressure drop in metallic foams. They are developed in the “surface evolverâ€‌ open source software. Mass, momentum, and energy equations, for air forced convection in open cell foams, are solved with a finiteelement method, for different values of cell size and porosity. Heat transfer and pressure drop results are reported in terms of volumetric Nusselt number and Darcy–Weisbach friction factor, respectively. Finally, a comparison between the numerical predictions obtained with the two foam models is carried out, in order to evaluate the feasibility to substitute the more complex and computationally heavier Weaire–Phelan foam structure with the simpler Kelvin foam representation. Negligible differences between the two models are exhibited at high porosities.