Steady propagation of a liquid plug in a two-dimensional channel
Steady propagation of a liquid plug in a two-dimensional channel
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DOI：
10.1115/1.1798051
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发表时间：
2004-10-01
影响因子：
1.7
通讯作者：
Grotberg, JB
中科院分区：
文献类型：
--
作者：
Fujioka, H;Grotberg, JB
在这项研究中，我们调查的稳定传播的液体塞内的二维通道内衬均匀，薄液膜。采用有限体积法求解了带自由表面边界条件的Navier-Stokes方程。我们研究的影响，不同的塞子传播速度和塞子长度的斯托克斯流动限制和有限的雷诺数（Re）。对于固定的栓塞长度，尾膜厚度随栓塞传播速度而增加。如果塞长度大于通道宽度，则尾膜厚度与先前的半无限气泡传播理论一致。随着塞长度减小到通道宽度以下，尾膜厚度减小，并且对于有限Re，在前导和尾膜之间存在显著的相互作用以及它们的局部流动效应。塞芯内部形成回流，随着Re的增加，回流向后弯月面偏斜。两个尖端之间的回流速度随塞长度而减小。宏观压力梯度是在流体性质和通道几何形状固定时，由堵塞长度划分的前导和拖尾气相之间的压降，是U和U-2的函数，其中U是堵塞传播速度。在塞长度较小时，U-2项变得占主导地位。在前弯月面处产生毛细波，其振幅随Re而增大，并且这导致壁面剪切应力和压力的大的局部变化。
In this study, we investigate the steady propagation of a liquid plug within a two-dimensional channel lined by a uniform, thin liquid film. The Navier-Stokes equations with free-surface boundary conditions art solved using the finite volume numerical scheme. We examine the effect of varying plug propagation speed and plug length in both the Stokes flow limit and for finite Reynolds number (Re). For a fixed plug length, the trailing film thickness increases with plug propagation speed. If the plug length is greater than the channel width, the trailing film thickness agrees with previous theories for semi-infinite bubble propagation. As the plug length decreases below the channel width, the trailing film thickness decreases, and for finite Re there is significant interaction between the leading and trailing menisci and their local flow effects. A recirculation flow forms inside the plug core and is skewed towards the rear meniscus as Re increases. The recirculation velocity between both tips decreases with the plug length. The macroscopic pressure gradient, which is the pressure drop between the leading and trailing gas phases divided by the plug length, is a function of U and U-2, where U is the plug propagation speed, when the fluid property and the channel geometry are fixed. The U-2 term becomes dominant at small values of the plug length. A capillary wave develops at the front meniscus, with an amplitude that increases with Re, and this causes large local changes in wall shear stresses and pressures.