【摘要】 针对传统蒙特卡洛法计算辐射传输耗时问题,提出了一种改进蒙特卡洛方法,通过比例迭代累加法来求解反射及散射能量,从而大幅减少了计算时间.引入直接评价方法,以包含参与性介质的密闭系统(方形和圆形为例)为例,分析了网格密度、发射能束数及物性参数对改进蒙特卡洛法计算精度的影响.当光学厚度为0.005时,采用改进蒙特卡洛方法求得方腔及圆形腔的表面微元辐射通量的相对均方根误差值分别为0.002 5及0.002 3,而采用传统蒙特卡洛方法时对应误差分别为0.008 0及0.003 7.可见,相同计算条件下,改进蒙特卡洛方法对辐射换热问题具有更高的精度.进一步研究了追踪能束数对计算误差的影响规律,给出了计算误差与追踪能束数拟合关系式,为计算该类问题的能束数选取提供了支撑.更多还原

【Abstract】 Aiming at the time-consuming problem of traditional Monte Carlo calculation for radiation transmission,this paper develops an improved Monte Carlo method,which solves the reflection and scattering energy through proportional iterative accumulation method,thereby greatly reducing the calculation time. The direct evaluation method is introduced,and the closed system containing participating media(square and circular as examples)is used as an example to analyze the influence of the grid density,the number of emitted energy beams and the physical parameters on the calculation accuracy of the improved Monte Carlo method. When the optical thickness is0.005,the relative root mean square error of radiation flux for the square cavity and the circular cavity is 0.002 5 and0.002 3 respectively by using the improved Monte Carlo method,while the corresponding errors are 0.008 0 and0.003 7 respectively when the traditional Monte Carlo method is used. It can be seen that under the same calculation conditions,the improved Monte Carlo method has higher accuracy for the radiation heat transfer problem. The influence of the tracking energy beam number on the calculation error is further studied,and the fitting relationship between the calculation error and the tracking energy beam number is given,which provides support for the selection of the energy beam number.更多还原