Evolution of nonconformal Landau-Levich-Bretherton films of partially wetting liquids
Evolution of nonconformal Landau-Levich-Bretherton films of partially wetting liquids
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DOI：
10.1103/physrevfluids.3.014203
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发表时间：
2018-01-19
影响因子：
2.7
通讯作者：
Khan, Saif A.
中科院分区：
文献类型：
--
作者：
Kreutzer, Michiel T.;Shah, Maulik S.;Khan, Saif A.
我们从实验和理论上描述了微通道中部分润湿液体的Landau-Levich-Bretherton膜的演化和最终破裂的动力学。虽然薄膜演化的早期动力学和破裂的接近崩塌动力学都已被理解，但我们匹配了这些区域，并从理论上发现无因次破裂时间T-r与kappa(-10/7)有关。这里，kappa是无量纲的曲率，由拉普拉斯压力间断的比率给出，拉普拉斯压力间断导致薄膜变薄，而分离压力的初始强度导致破裂。我们通过实验验证了破裂时间，并强调了数字微流体环境中早期薄膜破裂的关键后果：分段流动中的压降和液滴与壁面的隔离。
We experimentally and theoretically describe the dynamics of evolution and eventual rupture of Landau-Levich-Bretherton films of partially wetting liquids in microchannels in terms of nonplanar interface curvatures and disjoining pressure. While both the early-stage dynamics of film evolution and near-collapse dynamics of rupture are understood, we match these regimes and find theoretically that the dimensionless rupture time, T-r, scales with kappa(-10/7). Here, kappa is the dimensionless curvature given by the ratio of the Laplace-pressure discontinuity that initiates film thinning to the initial strength of the disjoining pressure that drives the rupture. We experimentally verify the rupture times and highlight the crucial consequences of early film rupture in digital microfluidic contexts: pressure drop in segmented flow and isolation of droplets from the walls.