Finite-element modeling of coupled radiative and diffusive heat transfer in nonparticipating media including symmetry and periodicity conditions

Thermal radiation exchanges in enclosures constituted of diffuse gray surfaces separated by a nonparticipating medium become a leading heat transfer mode as soon as high temperatures are involved. From the numerical point of view, radiation brings a strong nonlinearity that is difficult to handle due to couplings among all the surfaces. In this article, we present a finite-element implementation of coupled radiative and diffusive heat transfer in enclosures including symmetry or periodicity conditions. The formulation proposed enables us to define different solution strategies for the nonlinear finite element equations. Three-dimensional application examples show the efficiency of the proposed approach.