A simplified analytical model of radiative heat transfer in open cell foams

A simplified one-dimensional analytical model of radiative heat transfer in foams is presented, based on the idea of dividing the porous material into layers at the pore level and then modeling each layer of the porous material as an equivalent semi-transparent, absorbing and reflecting plane. Compared to existing models, the model proposed in this paper has the advantage of explicitly accounting for the geometry of the foam and the radiative energy fluxes, at the same time ensuring self-consistency and offering the computational lightness of analytical models, without sacrificing the mathematical simplicity of the formulation. Using a regular cubic lattice representation and assuming diffuse radiation, straightforward analytical correlations are derived to evaluate the characteristics both of single layers of foam and of finite thickness samples, accounting for various boundary conditions. The predictions of the model are in good agreement with experimental data taken from the literature.