采用低马赫数方法对空气射流破坏氦气分层现象的数值模拟  

Numerical Simulation of Erosion Phenomenon of Helium Stratification by Air Injection with Low Mach Number Algorithm

作　　者：侯炳旭[1] 俞冀阳[1] Dorothée Sénéchal 江光明[3] 闵皆昇 

机构地区：[1]清华大学工程物理系,北京100084 [2]法国电力公司研发中心,法国沙图78400 [3]中国核动力研究设计院核反应堆系统设计技术重点实验室,成都610041 [4]法国电力公司中国研发中心,北京100005

出　　处：《核动力工程》2015年第6期61-66,共6页Nuclear Power Engineering

基　　金：核反应堆系统设计技术国家级重点实验室基金(HT-A100K-02-2014006)

摘　　要：在对低速气体进行计算流体力学(CFD)数值模拟时,通常忽略气体的可压缩性。当计算体系中存在较大温差和较大组分浓度差时,不可压缩近似会因带来很大计算误差而失效。针对此问题,低马赫数方法通过将实际压力拆分为热力学压力和动力学压力的方式,将物性参数与热力学压力联系起来,在对不可压缩流动求解器进行较小改造后,较准确地处理低马赫数下的可压缩流问题。利用Code_Saturne程序实现该模型,并针对空气射流破坏轻密度气体分层现象进行模拟。首先通过网格敏感性分析,选定中等密度网格为计算网格;然后在比较不同算法的模拟结果中发现,采用低马赫数方法可以明显提高计算精度。最后,利用模拟结果,对空气射流破坏氦气分层实验中氦气的水平分布情况进行分析和讨论。The compressibility of gaseous mixture was usually neglect6d when doing CFD （Computation Fluid Dynamics） numerical simulation for low-speed gas flow. However, the non-compressible approximation is no longer valid when the temperature difference or the concentration difference is too large in the computation system and the computational error is unacceptable. A Low Mach Algorithm is developed to solve such a problem. By dividing the actual pressure into a Thermodynamic Pressure and a Mechanical Pressure, the algorithm combines the thermodynamic pressure with the physical properties and is able to simulate the low Mach compressible flow more precisely, with relatively tiny modification to the present incompressible solver. The algorithm was realized on Code_Saturne and was applied to simulate the erosion phenomenon of light gas stratification by air injection. In this paper, the mesh refinement sensitivity is firstly performed and the mesh with medium refinement is selected for the following computations. Then, after a comparison among the results by different algorithms, it is found that the Low Mach Algorithm improved the precision significantly. At last, with the obtained simulation results, the horizontal distribution of helium in the experiment is also analyzed and discussed.

关 键 词：计算流体力学 低马赫数方法 空气射流 氦气分层破坏 

分 类 号：TL334[核科学技术—核技术及应用]