Development of RTE solver for radiative transfer in absorbing-emitting medium using finite volume based CFD library OpenFOAM

In this study, the radiative transfer equation (RTE) solver radiationFoam within the Open Source Field Operation and Manipulation (OpenFOAM) C++ object-oriented framework is developed. As the RTE solver radiationFoam is recompiled based on the OpenFOAM C++ open source libraries, it inherits the main advantages of OpenFOAM software platform, such as the convenience of pre-processing for unstructured mesh generation by snappyHexMesh, MPI parallelization for domain-decomposition during calculation process, and post-processing with paraview. Particularly, the parameters required to solve RTE, such as the absorption coefficient, azimuthal and polar angles, and boundary conditions, could be easily set in the dictionary files. To verify the performance of radiationFoam, a preliminary test for classical benchmark problems of radiative transfer in absorbing-emitting medium is conducted. The RTE is discretized in solid angular space with the discrete ordinates method (DOM) and then integrated over both the control volume and solid angle with the finite volume method (FVM). The results obtained are compared with those previously reported in the literature to illustrate the performance and flexibility of the proposed method.