Discrete particle simulation of particle–fluid flow: model formulations and their applicability
Discrete particle simulation of particle–fluid flow: model formulations and their applicability
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DOI：
10.1017/s002211201000306x
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发表时间：
2010-08
影响因子：
3.7
通讯作者：
Zongyan Zhou;S. Kuang;Kaiwei Chu;A. Yu
中科院分区：
文献类型：
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作者：
Zongyan Zhou;S. Kuang;Kaiwei Chu;A. Yu
将连续流体的计算流体动力学（CFD）和离散颗粒的离散单元法（DEM）相结合的方法已越来越多地用于研究颗粒-流体耦合流动的基本原理。使用了不同的CFD-DEM模型。然而，这些模型的起源和适用性并不清楚。在本文中，不同的模型配方的起源进行了讨论。它表明，在连续体方法，三套配方存在于CFD-DEM方法：一个原始的格式集I，和随后的衍生物集II和集III，分别对应于所谓的模型A和模型B在文献中。对三种模型的适用性进行了理论分析，并通过对流化、气力输送和水力旋流器三种典型颗粒-流体流动系统的研究进行了验证。它表明，集I和II基本上是相同的，有小的差异，从不同的数学或数值处理的几个条款在原始方程。然而，第三组是第一组的简化版本。试验结果表明，这三种模型均适用于气体流态化，并在很大程度上适用于气力输送。但是，第三组的适用是有条件的，如水力旋流器的情况所示。严格来说，第三组仅在流体流动稳定且均匀时有效。第二组，特别是，第一组，这是在某种程度上被遗忘的文献中，建议为未来的CFD-DEM模拟复杂的颗粒流体流动。
The approach of combining computational fluid dynamics (CFD) for continuum fluid and the discrete element method (DEM) for discrete particles has been increasingly used to study the fundamentals of coupled particle–fluid flows. Different CFD–DEM models have been used. However, the origin and the applicability of these models are not clearly understood. In this paper, the origin of different model formulations is discussed first. It shows that, in connection with the continuum approach, three sets of formulations exist in the CFD–DEM approach: an original format set I, and subsequent derivations of set II and set III, respectively, corresponding to the so-called model A and model B in the literature. A comparison and the applicability of the three models are assessed theoretically and then verified from the study of three representative particle–fluid flow systems: fluidization, pneumatic conveying and hydrocyclones. It is demonstrated that sets I and II are essentially the same, with small differences resulting from different mathematical or numerical treatments of a few terms in the original equation. Set III is however a simplified version of set I. The testing cases show that all the three models are applicable to gas fluidization and, to a large extent, pneumatic conveying. However, the application of set III is conditional, as demonstrated in the case of hydrocyclones. Strictly speaking, set III is only valid when fluid flow is steady and uniform. Set II and, in particular, set I, which is somehow forgotten in the literature, are recommended for the future CFD–DEM modelling of complex particle–fluid flow.