Determination of simulation parameters in Monte Carlo ray tracing for radiative flux density distribution simulation

Determining appropriate simulation parameters in Monte Carlo Ray Tracing simulation, including receiver pixel size, micro-heliostat size and the number of rays, according to scene parameters, such as receiver size, heliostat size, slope error and slant range, can improve simulation accuracy while maintaining simulation efficiency. By means of simulation experiments and data fitting, the effects of simulation parameters on simulation accuracy and efficiency are studied in this paper. First, two evaluation metrics about the flux peak stability and distribution accuracy are proposed and the appropriate receiver pixel size, namely 0.1 m×0.1 m, is determined based on these metrics. Then, the optimal micro-heliostat size, namely 0.05 m×0.05 m, is determined under the condition of ensuring the flux distribution accuracy and simulation efficiency. Finally, when the flux distribution deviation converges to an acceptable value, the empirical functions between the minimum number of rays and the scene parameters are obtained for single-heliostat simulation and heliostat field simulation, respectively. The minimum number of rays is proportional to the area of the reflected ray cone base in single-heliostat simulation and is related to the cylindrical receiver radius and height in heliostat field simulation. The results are validated using practical heliostat field.