Effect of mass transfer on the film drainage between colliding drops
Effect of mass transfer on the film drainage between colliding drops
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DOI：
10.1016/j.jcis.2006.02.005
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发表时间：
2006-07-01
影响因子：
9.9
通讯作者：
Gourdon, C.
中科院分区：
文献类型：
--
作者：
Chevaillier, J. -P.;Klaseboer, E.;Gourdon, C.
本文通过实验研究了传质对浸没在另一种液体中的两个液滴之间以恒定接近速度碰撞的疏水行为的影响。所使用的液-液系统是硅油中的甘油。转移的溶质为丙酮，界面上的体积浓度差在1% ~ 5%之间。利用激光干涉测量技术测量了薄膜厚度的变化。研究了传质方向（从液滴到膜相或相反），并将结果与无传质情况进行了比较[E]。张建军，张建军，张建军，等。高分子材料的研究进展[j]。当溶质从液滴向连续相转移时，排水速率明显高于无传质情况。这一结果被解释为由于局部表面张力差异引起的传质引起的薄膜区域表面迁移（所谓的马兰戈尼效应）的结果。这种效果已经通过液滴和膜相的流动模式的可视化（使用粒子示踪技术）得到了证明。在这种情况下，膜高度的斜率作为时间的函数似乎与施加在液滴上的接近速度条件无关，似乎由界面张力梯度控制。相反，当溶质从连续相向液滴转移时，膜排水速率随传质强度的不同而降低，甚至趋近于零，甚至改变其符号。结果还表明，在研究的溶质浓度范围内，与润滑理论有效的尺度相比，传质对膜排水过程的影响发生在较大的距离上。(c) 2006爱思唯尔公司版权所有。
The influence of mass transfer on the drainage behaviour of the thin liquid film between two drops immersed in another liquid colliding at constant approach velocity has been studied experimentally. The liquid-liquid system used is glycerol in silicone oil. The transferred solute is acetone and the volume concentration difference across the interface ranges from 1 to 5%. The film thickness evolution has been measured using a laser interferometry technique. The direction of mass transfer (from the drops towards the film phase and inversely) has been investigated and the results compared to the case with no mass transfer [E. Klaseboer, J.P. Chevaillier, C. Gourdon, O. Masbernat, J. Colloid Interface Sci. 229 (2000) 274-285]. When the solute transfers from the drops towards the continuous phase, the drainage rate is significantly higher than in the case with no mass transfer. This result is interpreted as a consequence of the mass transfer induced surface mobility in the film region (the so-called Marangoni effect) due to localized surface tension differences. This effect has been demonstrated by the visualization of the flow patterns in the drops and in the film phase (using a particle tracer technique). In this case, the slope of the film height as a function of time seems to be independent of the approach velocity condition imposed on the drop and appears to be controlled by the interfacial tension gradient. In the opposite case, when the solute transfers from the continuous phase towards the drops, the film drainage rate is lowered with respect to the case of no mass transfer, goes to zero or even changes its sign depending on the mass transfer intensity. The results also show that in the range of solute concentration studied, the effect of mass transfer on the film drainage process takes place at large distances compared to the scales at which lubrication theory is valid. (c) 2006 Elsevier Inc. All rights reserved.