Rectangle CMFD Based on the 3D Method of Characteristics

三维特征线方法(the Method of Characteristics, MOC)作为确定论方法，能够满足中子输运求解的计算要求，并且有着优秀的几何适应性、较高的计算精度、简洁易实现的计算模型及强大的并行潜力，但是在高保真、精细化建模的需求下，它对计算量有着巨大的需求，因此需要一个加速方法来提高程序的计算效率，而粗网有限差分方法(coarse mesh finite difference method, CMFD)作为使用的较多的加速方法，能够取得非常显著的加速效果。本次研究基于三维特征线程序ANT-MOC，并使用自建计算模型对CMFD的加速效率和加速精度进行验证，最终结果表明本次研究的矩形CMFD方法在计算组件级的几何模型时能够节省10倍以上的计算时间，且在均匀矩形网格划分的情况下能实现无损加速。As a deterministic neutron transport solving method, the 3D method of characteristics (MOC) has excellent geometric adaptability, high calculation accuracy, simple and easy-to-implement computational model and strong parallel potential. However, under the demand of high-fidelity and refined modeling, it has a huge demand for computation, so it needs an acceleration method to improve the computational efficiency of the program, and the Coarse Mesh Finite Difference method (CMFD) is a widely used acceleration method that can achieve a very significant acceleration effect. In this study, we use ANT-MOC, a 3D MOC program, to count, and self-built calculation model is used to verify the acceleration efficiency and acceleration accuracy of CMFD. The final results show that the rectangular CMFD method can save more than 10 times the calculation time when calculating the component level geometry, and can achieve lossless acceleration in the case of uniform rectangular meshing.