Analytical model of radiative properties of packed beds and dispersed media

This paper presents an analytical formulation of radiative properties of statistically isotropic and homogeneous dispersed media in the geometric optic regime. It attempts to overcome the powerful but time consuming approaches based on ray-tracing Monte Carlo technique and advance the existing analytical models. We show that simple analytical formulas, allow to capture the main extinction mechanisms in a dispersed medium. The suitability of the proposed model is discussed through two comparative studies: firstly, with the ray-tracing Monte Carlo approach on radiative properties of packed beds of spheres and matrixes enclosing spherical cavities; and secondly, with the direct Monte Carlo simulation and literature data on hemispherical transmittances of packed beds of opaque and semi-transparent spheres. The computation time of the analytical approach is shown to be less significant than those of the ray-tracing Monte Carlo method. (C) 2013 Elsevier Ltd. All rights reserved.