Metallic foams: Radiative properties/comparison between different models

Abstract

The aim of this study is to determine the radiative properties, which are the extinction coefficient, the scattering albedo and the scattering phase function, of highly porous open-cell aluminium foam, using more-or-less simple predictive models, and to compare all these models. The radiative properties are predicted using geometric optics laws to model the interaction of radiation with the particles forming the foam. Moreover, the particles forming the foam are large compared with the considered wavelength and are supposed to be sufficiently distant from each other to scatter radiation independently. Thus, the radiative characteristics of the foam can be determined by adding the contributions of each particle. A particular attention is paid on microstructure analysis and modelling. We considered different kinds of cell shapes and struts cross-section, using microscopic and tomographic analysis. Furthermore, a new phase function modelling is presented. Finally, we compare the results of each method with the radiative properties obtained from experimental measurements of directional and hemispherical transmittances and hemispherical reflectance.