The effect of interfacial tension on secondary drop formation in electro-coalescence of water droplets in oil
The effect of interfacial tension on secondary drop formation in electro-coalescence of water droplets in oil
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DOI：
10.1016/j.ces.2011.07.019
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发表时间：
2011-11-01
影响因子：
4.7
通讯作者：
Ghadiri, Mojtaba
中科院分区：
文献类型：
--
作者：
Mousavichoubeh, Mirhamed;Shariaty-Niassar, Mojtaba;Ghadiri, Mojtaba
施加电场可以增强油中水滴的聚结作用。这种方法通常用于原油和石油行业将水从原油中分离出来。但是，在聚结过程中会形成细小的二次液滴。这显然是不可取的，因为分离更细的水滴变得更加困难。本文研究了表面活性剂操纵的界面张力和电场强度对二次液滴形成的影响。缩颈和泵送这两个相互竞争的过程决定了是否形成二次液滴。无量纲基团Weber数(描述电场引起的液滴变形和颈缩)和Ohnesorge数(描述在聚结过程中将水泵入连续相)可以耦合在一起，给出一个新的无量纲基团WO，描述形成的二次液滴的体积分数。WO数描述了导致缩颈的电应力能量与将粘性流体从液滴中抽出所需的能量之比。对于非离子和阴离子表面活性剂的使用以及电场强度所带来的大范围的界面张力，得到了很好的统一数据。这项工作的结果将有助于优化电聚并系统的设计。(C)2011爱思唯尔有限公司。保留所有权利。
The coalescence of water droplets in oils may be enhanced by application of an electric field. This approach is commonly used in the crude oil and petroleum industry to separate water from crude oil. However, the process could lead to the formation of fine secondary droplets during the process of coalescence. This is obviously undesirable, as it becomes more difficult to separate finer water droplets. In this work the effects of interfacial tension, manipulated by the use of surfactants, and electric field strength on the formation of secondary droplets are investigated. Two competing processes of necking and pumping determine whether secondary droplets are formed. The dimensionless groups Weber Number (describing droplet deformation and necking due to the electric field) and Ohnesorge Number (describing the pumping of water into the continuous phase in the process of coalescence) may be coupled to give a new dimensionless group WO, describing the volume fraction of secondary droplets that are formed. WO Number describes the ratio of the electrical stress energy that causes necking over the energy required for pumping the viscous fluid out of the droplets. For a wide range of interfacial tensions, brought about by the use of non-ionic and anionic surfactants and electric field strengths, a good unification of data is obtained. The outcome of this work will be useful for optimizing the design of the electro-coalescence systems. (C) 2011 Elsevier Ltd. All rights reserved.