离散模拟的粒子-边界作用模型  

Particle-wall interaction model in discrete simulation

作　　者：沈国飞[1,2] 王利民[1,2] 葛蔚[1] 李曦鹏[1,2] 

机构地区：[1]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《计算机与应用化学》2009年第5期539-544,共6页Computers and Applied Chemistry

基　　金：国家自然科学基金资助项目(20336040)

摘　　要：粒子-边界作用模型是粒子模拟中非常重要的一类边界条件,主要包括镜面反射、回弹反射和热边界等。本文详细介绍了这几类边界条件,重点分析讨论了几种模型中涉及的Maxwell分布和偏Maxwell分布以及它们在计算机模拟中的实现方式,并用硬球对流体做了模拟测试。模拟结果表明,对于热平衡状态下的流体,壁面反射粒子速度用Maxwell分布模拟的流体温度比边界要低,二维情况下只有壁面温度的约0.70,三维情况下则约为0.77。并且流体温度不是处处相等,靠近壁面处比其他地方要显得更低,而用偏Maxwell分布模拟的流体状态则与实际情形吻合的很好。Particle-wall interaction models, including specular reections, bounce-back reflections and diffuse reflections and so on, are very important boundary conditions in particle simulations. These boundary conditions are reviewed in this paper, and the focus is on several models related to Maxwellian distribution and Biased-Maxwellian distribution, as well as their implementation in computer simulations of the heat balance between the fluid and boundaries. Comparing the simulation results with the actual situation, it is proved that Maxwellian distribution will lead to the loss of energy in the bulk. For a fluid in equilibrium with a boundary, the temperature of the fluid, as measured, is only about 0. 70 of the target value if Maxwellian distribution is applied in two-dimensional cases, and 0. 77 in three-dimensional cases. And it is not uniform everywhere, lower temperature is found near the boundary. Apparently, it is shown that in diffuse reflections, the particles leaving wall boundaries should have Biased-Maxwellian velocity distribution while a Maxwellian distribution is to be reconstructed in the bulk.

关 键 词：边界条件 计算机模拟 Maxwell分布 偏Maxwell分布 

分 类 号：TQ015.9[化学工程] TP183[自动化与计算机技术—控制理论与控制工程]