Analysis of inertial migration of neutrally buoyant particle suspensions in a planar Poiseuille flow with a coupled lattice Boltzmann method-discrete element method
Analysis of inertial migration of neutrally buoyant particle suspensions in a planar Poiseuille flow with a coupled lattice Boltzmann method-discrete element method
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DOI：
10.1063/1.5095758
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发表时间：
2019-06
影响因子：
4.6
通讯作者：
Wenwei Liu;Chuan-Yu Wu
中科院分区：
文献类型：
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作者：
Wenwei Liu;Chuan-Yu Wu
在本研究中，利用单弛豫时间格子玻尔兹曼方法和赫兹接触理论实现的离散元方法建立了用于模拟固液多相流的混合数值框架。然后采用数值框架系统地探讨颗粒浓度对平面泊肃叶流中中性浮力颗粒悬浮液惯性迁移的影响。结果表明，颗粒浓度对迁移的影响主要由特征通道雷诺数Re0决定。对于相对较低的Re0（Re0˂20），只能在非常低的颗粒浓度（≤5%）下观察到迁移行为。然而，当Re0˃20在高浓度（≥20%）时可以观察到迁移行为。此外，提出了聚焦数Fc来表征惯性迁移的程度。研究发现，根据聚焦数 Fc+ 和 Fc- 的两个临界值，惯性偏移可分为三种状态： i) 当 Fc˃Fc+ 时，发生完全惯性偏移； ii) 当Fc˂Fc-时，粒子横向未聚焦； iii) 当Fc-˂Fc˂Fc+时，发生部分惯性迁移。
In this study a hybrid numerical framework for modelling solid-liquid multiphase flow is established with a single-relaxation-time lattice Boltzmann method and the discrete element method implemented with the Hertz contact theory. The numerical framework is then employed to systematically explore the effect of particle concentration on the inertial migration of neutrally buoyant particle suspensions in planar Poiseuille flow. The results show that the influence of particle concentration on the migration is primarily determined by the characteristic channel Reynolds number Re0. For relatively low Re0 (Re0˂20), the migration behaviour can only be observed at a very low particle concentration (≤5%). However, when Re0˃20 the migration behaviour can be observed at a high concentration (≥20%). Furthermore, a focusing number Fc is proposed to characterise the degree of inertial migration. It was found that the inertial migration can be classified into three regimes depending on two critical values of the focusing number, Fc+ and Fc-: i) when Fc˃Fc+, a full inertial migration occurs; ii) when Fc˂Fc-, particles are laterally unfocused; iii) when Fc-˂Fc˂Fc+, a partially inertial migration takes place.