Interfacial settling mode and tail dynamics of spherical-particle motion through immiscible fluids interfaces
Interfacial settling mode and tail dynamics of spherical-particle motion through immiscible fluids interfaces
复制标题
DOI：
10.1016/j.ces.2020.116091
复制
发表时间：
2021-01
影响因子：
4.7
通讯作者：
Zhiqiang Chen;Moran Wang;Shiyi Chen
中科院分区：
文献类型：
--
作者：
Zhiqiang Chen;Moran Wang;Shiyi Chen
颗粒在流体-流体界面中的运动是学术界和工业界的共同兴趣，然而，其基本机制尚未完全理解。在这项工作中，两相LBM-DEM耦合模型的发展，系统地探讨了在不同的物理条件下，通过不混溶的流体-流体界面的颗粒运动的行为。经过验证，本模型成功地再现了两种典型的界面变形模式，薄膜排水模式和尾矿模式。结果表明，雷诺数（Re = RV/ν）并不是决定界面沉降模式的关键参数，因为较大的上层流体粘度（ν）导致的较小的Re有利于拖尾模式的发生，而较小的颗粒半径（R）或较小的沉降速度（V）导致的较小的Re则更容易导致膜状排水模式的发生。毛细管数（Ca）和粘度比（λ）图中的状态图表明，存在一个临界Ca，它表征了从膜状排水模式向拖尾模式的转变，该临界Ca几乎与粘度比（λ）无关，但随颗粒尺寸（R）的减小而增大。尾部动力学分析表明，尾长越大，夹断位置越靠近尾部中部。
Particles motion through a fluid-fluid interface is of both academic and industrial interests, yet, underlying mechanisms have not been fully understood. In this work, a two-phase LBM-DEM coupling model is developed to systematically explore the behavior of a particle moving through an immiscible fluid-fluid interface under different physical conditions. After validations, the current model reproduces two typical interface deformation modes, film drainage mode and tailing mode, successfully. The numerical results reveal that Reynolds number (Re = RV/ν) is not the key parameter governing the interfacial settling mode, because a smallerRefrom larger upper fluid viscosity (ν) is conducive to the occurrence of tailing mode, but a smallerRefrom smaller particle radius (R) or smaller settling velocity (V) makes film drainage mode take place more easily. The regime map in Capillary number (Ca) and viscosity ratio (λ) diagram shows that there exists a criticalCacharacterizing the transition from film drainage mode to tailing mode, which is nearly independent of the viscosity ratio (λ) yet increases with the reduced particle size (R). The tail dynamics analysis shows that a higherCaresults in a larger final tail length and a pinch-off position closer to the middle of tail.