Modeling and simulation of particle agglomeration in turbulent flows using a hard-sphere model with deterministic collision detection and enhanced structure models
Modeling and simulation of particle agglomeration in turbulent flows using a hard-sphere model with deterministic collision detection and enhanced structure models
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DOI：
10.1016/j.ijmultiphaseflow.2015.03.018
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发表时间：
2015-07-01
影响因子：
3.8
通讯作者：
Almohammed, N.
中科院分区：
文献类型：
--
作者：
Breuer, M.;Almohammed, N.
本文研究了刚性、干燥和静电中性颗粒在湍流气流中的团聚问题。基于描述离散颗粒流的欧拉-拉格朗日方法框架下的确定性碰撞模型，对Kosinski和Hoffmann（2010）的凝聚模型中碰撞时间的确定进行了改进。凝聚模型的应用领域扩展到全三维湍流模拟的大涡模拟技术。此外，该模型通过引入三种不同的概念来模拟所产生的团聚体的结构，即体积等效球模型，惯性等效球模型和紧密堆积球模型。此外，所得到的模拟策略的湍流颗粒负载剪切流的第一次分析和评价有关的三个结构模型。然后，扩展团聚模型的性能进行了测试，通过调查各种模拟参数的影响，如恢复和摩擦系数的颗粒，包含的双向耦合，亚网格尺度模型的颗粒，升力，壁面粗糙度和颗粒的质量负载上的团聚过程中的湍流颗粒负载的垂直通道流。在参数研究中，仅采用紧密堆积的球体模型，因为它考虑了团聚颗粒之间的间隙空间，并且还满足质量和角动量守恒。基于结果，可以得出结论，增强团聚模型使用紧密堆积的球体模型所产生的团聚体现实地预测内的颗粒负载流的团聚过程的物理行为。(C)2015爱思唯尔有限公司版权所有。
The present paper is concerned with the modeling and simulation of particle agglomeration of rigid, dry and electrostatically neutral particles in turbulent gas flows. Based on a deterministic collision model in the framework of an Euler-Lagrange approach for the description of disperse particle-laden flows, the original agglomeration model of Kosinski and Hoffmann (2010) is improved regarding the determination of the collision time. The application area of the agglomeration model is extended towards fully three-dimensional turbulent flows simulated by the large-eddy simulation technique. Additionally, the model is enhanced by introducing three different concepts to model the structure of the arising agglomerate, namely the volume-equivalent sphere model, the inertia-equivalent sphere model and the closely-packed sphere model. Furthermore, the resulting simulation strategy for turbulent particle-laden shear flows is first analyzed and evaluated concerning the three structure models. Then, the performance of the extended agglomeration model is tested by investigating the influence of various simulation parameters such as the restitution and friction coefficients of the particles, the inclusion of the two-way coupling, the subgrid-scale model for the particles, the lift forces, the wall roughness and the particle mass loading on the agglomeration process in a turbulent particle-laden vertical channel flow. In the parameter study solely the closely-packed sphere model is adopted, since it takes the interstitial space between the agglomerated particles into account and additionally satisfies the conservation of mass and angular momentum. Based on the results, it can be concluded that the enhanced agglomeration model using the closely-packed sphere model for the arising agglomerate realistically predicts the physical behavior of the agglomeration process within particle-laden flows. (C) 2015 Elsevier Ltd. All rights reserved.