Capillary threads and viscous droplets in square microchannels
Capillary threads and viscous droplets in square microchannels
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DOI：
10.1063/1.2911716
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发表时间：
2008-05-01
影响因子：
4.6
通讯作者：
Mason, Thomas G.
中科院分区：
文献类型：
--
作者：
Cubaud, Thomas;Mason, Thomas G.
我们通过方形微通道中的流体动力聚焦实验研究了含有较多粘性液体的螺纹的形成和演化，周围环绕着较少粘性、不相容的液体。在较大的粘度和界面张力范围内，确定了流动行为的五个特征区域：穿线、喷射、滴落、管状和置换。我们根据每种流体的毛细管数在流动图上定位这些区域之间的边界。在喷射和滴落过程中，液滴的大小是测量的，并与流体性质、流动参数和几何形状有关。文中还讨论了液滴喷出前的临界螺纹长度和滴滴破裂前粘性尾巴的临界长度。这项研究分类并定义了可用于在基本微流控几何形状中产生超通道和子通道尺寸的粘性液滴的线程不稳定性区域。(C)2008年美国物理研究所。
We experimentally study the formation and evolution of threads containing more viscous liquids surrounded by less viscous, immiscible liquids through hydrodynamic focusing in square microchannels. Over a large range of viscosities and interfacial tensions, five characteristic regimes of flow behavior are identified: threading, jetting, dripping, tubing, and displacement. We locate the boundaries between these regimes on a flow map based on the capillary number of each fluid. In the jetting and the dripping regimes, the droplet size is measured and related to fluid properties, flow parameters, and geometry. The critical thread length before jetting droplets and the critical length of a viscous tail before breakup in dripping are also examined. This study classifies and defines regimes of thread instabilities that can be used to produce supra- and subchannel size viscous droplets in an elementary microfluidic geometry. (C) 2008 American Institute of Physics.