CFD-DEM modelling of multiphase flow in dense medium cyclones
CFD-DEM modelling of multiphase flow in dense medium cyclones
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DOI：
10.1016/j.powtec.2009.03.015
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发表时间：
2009-08-10
影响因子：
5.2
通讯作者：
Vince, A.
中科院分区：
文献类型：
--
作者：
Chu, K. W.;Wang, B.;Vince, A.
重介质旋流器（DMC）是选煤过程中广泛使用的一种大吨位原煤提质设备。它设计简单，但由于进料和工艺介质固体的尺寸和密度分布以及形成的湍流涡流，其内部的流型复杂。本文将离散元法（DEM）与计算流体力学（CFD）相结合，建立了描述该流动系统的数学模型。离散元模型是用来模拟离散颗粒的运动，通过应用牛顿的运动定律。计算流体动力学（CFD）通过数值求解局部平均Navier-Stokes方程来模拟浆体介质的运动，该方程由流体体积（VOF）和混合物多相流模型提供。该方法被证明是能够再现典型的流动现象，在DMC。分析了中煤比的影响和所谓的“喘振”现象。试图解释观察到的现象中的粒子粒子，粒子流体和粒子壁的相互作用力。该方法提供了一种方便的方法来检查DMC的流动和性能的几何，材料和操作条件。(C)2009爱思唯尔有限公司版权所有。
Dense medium cyclone (DMC) is a high-tonnage device that is widely used to upgrade run-of-mine coal in coal preparation. It is simple in design but the flow pattern within it is complex due to the size and density distributions of the feed and process medium solids, and the turbulent vortex formed. This paper presents a mathematical model to describe this flow system by means of combining Discrete Element Method (DEM) with Computational Fluid Dynamics (CFD). The DEM is used to model the motion of discrete particles by applying Newton's laws of motion. The CFD is used to model the motion of slurry medium by numerically solving the local-averaged Navier-Stokes equations facilitated with the Volume of Fluid (VOF) and Mixture multiphase flow models. The approach is shown to be able to reproduce typical flow phenomena in DMCs. The effect of medium-to-coal ratio and the so-called "surging" phenomenon are analyzed. An attempt is made to explain the observed phenomena in terms of particle-particle, particle-fluid and particle-wall interaction forces. The approach offers a convenient way to examine the flow and performance of DMC in relation to geometric, material and operational conditions. (C) 2009 Elsevier B.V. All rights reserved.