Abstract 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 smaller Re from larger upper fluid viscosity (ν) is conducive to the occurrence of tailing mode, but a smaller Re from 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 critical Ca characterizing 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 higher Ca results in a larger final tail length and a pinch-off position closer to the middle of tail.

中文翻译：

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通过不混溶流体界面的球粒运动的界面沉降模式和尾部动力学

摘要 通过流体-流体界面的粒子运动具有学术和工业兴趣，但其潜在机制尚未完全了解。在这项工作中，开发了一个两相 LBM-DEM 耦合模型，以系统地探索粒子在不同物理条件下穿过不混溶流体 - 流体界面的行为。经验证，当前模型成功再现了两种典型的界面变形模式，薄膜排水模式和拖尾模式。数值结果表明，雷诺数（Re = RV/ν）不是控制界面沉降模式的关键参数，因为较大的上部流体粘度（ν）导致较小的 Re 有利于拖尾模式的发生，但较小的粒子半径 (R) 或较小的沉降速度 (V) 导致较小的 Re 使薄膜排水模式更容易发生。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 表征从薄膜排水模式到拖尾模式的转变，它几乎与粘度比 (λ) 无关，但随着降低粒径 (R)。尾部动力学分析表明，较高的 Ca 导致更大的最终尾部长度和更接近尾部中部的夹断位置。