Solution of radiative intensity with high directional resolution in heterogeneous participating media and irregular geometries by the null-collision reverse Monte Carlo method

Abstract Radiative intensity with high directional resolution is very useful for many inverse analyses. In this work, the null-collision algorithm is combined with the reverse Monte Carlo method to calculate radiative intensity with high directional resolution in heterogeneous participating media and irregular geometries. A convergence criterion by monitoring the standard deviation of Monte Carlo weights is proposed to determine the required number of energy bundles and to estimate the accuracy of the Null-Collision Reverse Monte Carlo (NC-RMC) method. Then, directional radiative intensity in heterogeneous participating media of three-dimensional cubic and irregular geometries is calculated. Results show that the accuracy of the NC-RMC method is well predicted by the proposed convergence criterion and very good accuracy is achieved by setting strict convergence condition. Meanwhile, with the same obtained accuracy, the NC-RMC method has better computing efficiency than the standard reverse Monte Carlo method. For the radiative system with heterogeneous participating medium and irregular geometry, the NC-RMC method shows a distinct advantage in ease of programming and program portability. Results in this work show that the NC-RMC method is a good choice to solve radiative intensity in heterogeneous media and/or radiative systems with irregular geometries, which is very useful for inverse analysis in combustion systems.