Quantitative comparison of the DRESOR and Monte Carlo methods for calculating radiative heat flux

The Monte Carlo method (MCM) can be used to calculate the radiative heat flux and divergence with high accuracy, and the Distribution of Ratios of Energy Scattered by the medium Or Reflected by the boundary surface (DRESOR) method based on the MCM provides the radiation intensity with high directional resolution. However, the accuracy and efficiency of the DRESOR method for calculating the radiative heat flux and divergence have not been verified. Therefore, in this article, the DRESOR method is reformed to make it more suitable for calculating the radiative heat flux and divergence, and the DRESOR method and MCM are compared quantitatively. In the comparison, the influences of the Mean Optical Thickness per Element (MOTE), the surface and medium parameters, anisotropic scattering, and a nonuniform medium are considered. The results show that the figure of merit (FoM) of the reformed DRESOR method is 81.18 and 6.04 times that of the MCM for the surface element and space element, respectively when the MOTE is 0.17 for calculating the radiative heat flux and divergence. The larger the surface emissivity, and the smaller the scattering albedo, the better the performance of the DRESOR method than the MCM is. Meanwhile, the MOTE (mesh density), anisotropic scattering, and the nonuniform medium have similar influences on the DRESOR method and the MCM.