活动滴的浮力驱动的吸引力
Yibo Chen1, Kai Leong Chong2, Haoran Liu1
1Physics of Fluids Group, Max Planck Center for Complex Fluid Dynamics and J.M.Burgers Center for Fluid Dynamics, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
这项研究揭示了浮力效应,经常被忽视,驱动活跃的油滴吸引和集群,与典型的马兰戈尼排斥形成鲜明对比. 增加的溶性雷利数 (Ra) 促进了吸引力和碰撞,而利略数 (Ga) 则延迟了它们.
科学领域:
- 软物质物理学 软物质物理学
- 流体动力学 流体动力学
- 化学工程是化学工程的重要组成部分.
背景情况:
- 环境液体中的活性油滴通常会由于马兰戈尼效应而表现出排斥性相互作用.
- 由于密度差异而产生的浮力效应在研究活跃滴滴相互作用时经常被忽视.
- 最近的实验表明,浮力驱动的对流可以导致活跃的滴滴聚类.
研究的目的:
- 以数值研究浮力效应对活跃油滴相互作用和行为的作用.
- 分析浮力如何,除了马兰戈尼流,影响滴滴的吸引和排斥.
- 为了确定滴滴相互作用对关键控制参数的依赖性:Péclet数 (Pe),利略数 (Ga) 和溶性雷利数 (Ra).
主要方法:
- 使用数值模拟来建模活跃油滴动态.
- 该研究包括马兰戈尼驱动的推进 (Pe) 和浮力效应 (Ga,Ra).
- 分析侧重于在不同的参数条件下邻近滴的吸引和排斥行为.
主要成果:
- 马兰戈尼效应导致滴滴排斥,而反应产品的浮力会诱导吸引力.
- 足够高的溶性雷利数 (Ra) 可以导致滴滴碰撞.
- 增加利略数字 (Ga) 延迟了滴滴碰撞.
- 吸引速度 (红) 与Ra^{1/4) /{l/R}成正比,排斥速度 (重复) 与Pe*Ra^{-0.38) 成正比.
结论:
- 浮力效应,特别是扩散产品的浮力效应,对于控制活跃滴滴相互作用至关重要,并且可以克服Marangoni排斥.
- 吸引力 (浮力) 和排斥力 (Marangoni) 之间的相互作用决定了滴滴聚合和碰撞动态.
- 一个平衡条件 (Pe ~ Ra^0.63) 准确地预测了非碰撞和碰撞模式之间的过渡.
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