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Numerical Analysis of Dense Phase Particulate Flow using Special Computer for Particle Model (MD GRAPE)

使用颗粒模型专用计算机 (MD GRAPE) 进行密相颗粒流数值分析

基本信息

批准号：
07555379
负责人：
TSUJI Yutaka
金额：
$ 0.38万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Numerical calculation of particle motion under the conditions of nongravity and vacuum was performed to investigate the performance of special computer for particle model (GRAPE). All individual particles are charged. The Coulomb force acts on particles. Usually, the particle-particle interaction is considered between neighboring particles in discrete particle simulation. However, the effect of remote particles must be considered when dealing with the Coulomb force. The great ability of the special computer (GRAPE) is expected in such circumstances. It was found in the present work that significant ability of GRAPE is manifested as the number of particles increases. Moreover, we developed a method for efficient treatment of contact of particles. By combining this method with GRAPE,the computation time can be further reduced.Along with the above study, we developed an algorithm to calculate particle motion influenced by static electricity. We attempted an approximate treatment by averaging the effects of remote particles on a particle considered. The regions is divided into small cells in which several particles exist. When considering the effect of particles in a cell on a particle far from the cell, electric charge of all particles in the cell is summed and the force acting on the remote particle due to the assembly of these particles is calculated based on the summed charge. We call this method "grouping method." Several grouping methods were considered depending on how to obtain the gravitational point of the assembly of particles. In this work, the difference in calculated results between grouping methods was studied.Also, to enlarge applicability of the discrete particle simulation, various cases were investigated : the relation between the 2D and 3D calculations, the effects of non-sphericity and so on.

为了考察粒子模型专用计算机GRAPE的性能，对无重力和真空条件下的粒子运动进行了数值计算。所有的粒子都是带电的。库仑力作用在粒子上。在离散粒子模拟中，通常考虑相邻粒子之间的相互作用。然而，在处理库仑力时，必须考虑远程粒子的影响。在这种情况下，专用计算机（GRAPE）的强大功能是人们所期望的。在本工作中发现，随着颗粒数量的增加，GRAPE表现出显着的能力。此外，我们开发了一种有效处理颗粒接触的方法。沿着上述研究，我们发展了一种计算静电作用下质点运动的算法。我们尝试了一种近似的处理方法，即把遥远粒子对所考虑粒子的影响取平均值。这些区域被划分为小单元，其中存在几个粒子。当考虑单元中的粒子对远离单元的粒子的影响时，将单元中的所有粒子的电荷相加，并且基于相加的电荷计算由于这些粒子的聚集而作用在远程粒子上的力。我们称这种方法为“分组法”。“根据如何获得粒子集合的引力点，考虑了几种分组方法。本研究对不同分组方法计算结果的差异进行了研究，同时，为了扩大离散粒子模拟的适用性，对二维和三维计算的关系、非球形的影响等各种情况进行了研究。