Solving transient coupled conductive and radiative transfers in porous media with a Monte Carlo Method: Characterization of thermal conductivity of foams using a numerical Flash Method

Abstract

This paper presents a single Monte-Carlo algorithm used to solve transient conductive and radiative heat transfers in three-dimensional porous media. The complete methodology presented step by step herein enables practical and efficient study of geometrical and multiphysical complexities. The code was validated against results obtained by commercial software, analytical and semi-analytical solutions. Computation times were found to be greatly reduced when radiative transfer is predominant compared with those obtained using a deterministic solver. This kind of approach allows a probe calculation in the frame of linear thermal transfers and is well suited for the numerical characterization of heterogeneous media. In this work a numerical flash method was reproduced and enabled us to evaluate the effective total conductivity of the equivalent homogenized medium. The influence of various parameters such as porosity, size of the unit cell, bulk conductivity of the solid phase, reference temperature and emissivity was studied for a stack of Kelvin cells. This tool enables the parametric investigation of geometric and thermal properties. The results are in good agreement with those of the literature.