An equation-solving method based on radiation distribution factor for radiative transfer in participating media with diffuse boundaries

Abstract

An efficient and accurate method to solve the directional radiation intensity in the participating medium has always been a pursuit in radiative transfer fields, especially in radiation detection and inverse radiative transfer problems. As one of the few algorithms with both high accuracy and strong applicability, the reverse Monte Carlo (RMC) method suffers from the disadvantages of unavoidable random statistical errors and time-consuming ray tracing. Recently, a so-called equation-solving integral equation method based on the radiation distribution factor (ES-RDFIEM) can effectively overcome these shortcomings of RMC, which has comparable accuracy as RMC while taking only a few hundredths or thousandths of the calculation time of RMC. In this paper, ES-RDFIEM was extended to a radiation system with diffuse surfaces by constructing the radiative transfer equation (RTE) about the radiation distribution factor (RDF) of the wall and internal medium, respectively. The mathematical principle and formula were introduced in detail, and the computational performance was examined by several samples with different radiative parameters. The results showed that the RDF and radiation intensity solved by ES-RDFIEM are in good agreement with RMC, and ES-RDFIEM is more stable and reliable. More importantly, the computation time of ES-RDFIEM is significantly shorter than that of RMC, and it is not affected by wall emissivity, internal medium optical thickness and scattering albedo.