| 热辐射输运问题的高效蒙特卡罗模拟方法 |
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| 引用本文： | 许育培,李树.热辐射输运问题的高效蒙特卡罗模拟方法[J].物理学报,2020(2):321-329. |
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| 作者姓名： | 许育培 李树 |
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| 作者单位： | 北京应用物理与计算数学研究所;中国工程物理研究院研究生院 |
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| 基金项目： | 中国工程物理研究院于敏基金(批准号:FZ025);国家自然科学基金(批准号:11775033,11775030)资助的课题~~ |
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| 摘 要： | 惯性约束聚变研究中,热辐射光子在介质中的输运以及热辐射光子与介质的相互作用是重要研究课题,蒙特卡罗方法是该类问题的重要研究手段之一.隐式蒙特卡罗方法虽然能正确地模拟热辐射在介质中的输运过程,但当模拟重介质(材料的吸收系数大)问题时,该方法花费的计算时间将变得很长,导致模拟效率很低.本文以离散扩散蒙特卡罗方法为基础,开发了"离散扩散蒙特卡罗方法辐射输运模拟程序",可以较好地解决重介质区的计算效率问题,但是离散扩散蒙卡罗方法在模拟轻介质区时精度不够高.辐射输运问题中通常既有轻介质也有重介质,为了能同时解决蒙特卡罗方法模拟的效率和精度问题,本文研究了离散扩散蒙特卡罗方法与隐式蒙特卡罗方法相结合的模拟方法,并提出了新的扩散区与输运区界面处理方法,研制了混合蒙特卡罗方法的辐射输运模拟程序.典型辐射输运问题模拟显示:在模拟重介质问题时,该程序能大幅缩短模拟时间,且能取得与隐式蒙特卡罗方法一致的结果;在模拟轻重介质均存在的问题时,与隐式蒙特卡罗方法相比,混合蒙特卡罗方法的模拟精度与其相当且计算效率同样能够得到显著提升.
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| 关 键 词： | 热辐射输运 隐式蒙特卡罗 离散扩散蒙特卡罗 界面处理方法 |
An efficient Monte Carlo simulation method for thermal radiation transport |
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| Xu Yu-Pei,Li Shu.An efficient Monte Carlo simulation method for thermal radiation transport[J].Acta Physica Sinica,2020(2):321-329. |
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| Authors: | Xu Yu-Pei Li Shu |
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| Affiliation: | (Institute of Applied Physics and Computational Mathematics,Beijing 100094,China;Graduate School of China Academy of Engineering Physics,Beijing 100088,China) |
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| Abstract: | Thermal radiation transfer in material and the interaction between radiative photon and material are important research projects of the inertial confinement fusion,and Monte Carlo method is one of the important researching methods.Based on the implicit integral-differential transport equation,traditional implicit Monte Carlo method can accurately simulate the thermal radiation transport in material.However,the implicit Monte Carlo method would take quite a long computational time when the opacity is increased because scattering events are dominant in particles’histories,thus reducing the simulation efficiency.In this paper,based on discrete diffusion Monte Carlo method,i.e.a radiation transport code,the discrete diffusion Monte Carlo radiation transport simulation,is developed.The code increases the efficiency of thermal radiation simulations in a high opacity range,but it can yield insufficiently accurate results in a low opacity range.There exist low opacity material and high opacity material in the inertial confinement fusion.In this work,investigated are several numerical techniques that can improve the utility and accuracy of discrete diffusion Monte Carlo for grey thermal radiation simulation.First,the discrete diffusion Monte Carlo method and implicit Monte Carlo method are combined.Second,a new method of treating the interface between the diffusive region and the transport region is proposed.Finally,a hybrid radiative transfer program is developed.In order to verify the hybrid radiative transfer program and the new interface method,a series of numerical experiments for typical thermal radiation transport problem is conducted.In these problems,materials with different opacities are tested.Then the simulation efficiencies and curves of temperature,obtained by the two Monte Carlo methods,are analyzed.According to the simulation results,the program can not only accurately simulate the radiation transport in material with high opacity,but also remarkably increase the simulation efficiency.This is because many implicit Monte Carlo steps are substituted by one diffusive step and the details in the diffusive step are ignored.Also,the propagation of thermal radiation depicted with figures and tables are consistent with the radiation transport theory.In addition,the results from the hybrid Monte Carlo method reach the same accuracy as that from the implicit Monte Carlo method,and the simulation efficiency is remarkably increased. |
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| Keywords: | thermal radiation transport implicit Monte Carlo method discrete diffusion Monte Carlo method interface methods |
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