Solution of radiative heat transfer problems with the discrete transfer method applied to triangular meshes

The present communication deals with the solution of the radiative transfer equation in a gray absorbing media. The solution is performed on unstructured triangular meshes using the discrete transfer method (DTM). The application of the DTM to triangular meshes is detailed and discussed. The developed code is validated with benchmark cases and applied to pure radiative problem (with and without evaluation of the source term). The approach shows very good performances for the wall heat transfer evaluation. The discrete transfer method also presents a particular ray effect. This effect is clearly brought up with the study of radiative equilibrium between eccentric cylinders: wiggles can appear in the temperature field. To reduce this ray effect, the use of a great amount of rays is required to get a smooth (i.e. wiggle free) solution, in the case of pure radiative problems. The solution of coupled conductive–radiative problems or convective–radiative heat transfer necessitates less rays to obtain a converged solution.