Improved integral equation method based on radiation distribution factors for high-resolution radiative intensity in graded index media.

Abstract An improved integral equation method based on radiation distribution factors (RDFIEM) is developed to solve the radiative intensity with high directional resolution in semitransparent media with graded refractive index (GRI). The radiation distribution factors (RDFs) are solved by using the reverse Monte Carlo curved ray tracing technique (RMCCRT). Based on the RDFs, the source terms along the curved ray path decided by the Fermat principle are predicted accurately. Then, the integral equation method (IEM) is employed to solve the radiative intensity through integral along the curved ray path. One-dimensional and two-dimensional test cases are done, and all the results show that the RDFIEM is not only flexible in treating directional radiation problems but also very accurate and efficient. Highlights • RDFIEM is developed to solve radiative intensity with high directional resolution. • RDFIEM simplifies the integral process while retains the high accuracy of IEM. • Effects of radiative properties on radiative intensity are investigated. [ABSTRACT FROM AUTHOR]