Influence of DC electric field upon the production of oil-in-water-in-oil double emulsions in upwards mm-scale channels at low electric field strength
Influence of DC electric field upon the production of oil-in-water-in-oil double emulsions in upwards mm-scale channels at low electric field strength
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DOI：
10.1016/j.expthermflusci.2016.10.023
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发表时间：
2017-02-01
影响因子：
3.2
通讯作者：
Simmons, Mark J. H.
中科院分区：
文献类型：
--
作者：
Alberini, Federico;Dapelo, Davide;Simmons, Mark J. H.
提出并描述了一种新的O/W/O生成方法，以实现均匀的油滴大小，并覆盖薄层水。通过在不同内径(ID)的针(O/W乳状液从其向上射入连续油相)和位于距针尖选定距离的接地金属环之间施加直流电场，产生液滴。与以前的技术相比，该技术的优点在于可以利用低电场控制水的液滴大小和涂层。应用高速成像技术测定了不同流动和电场条件下的液滴尺寸。在没有电场的情况下，观察到了几种流动状态；在雷诺数从80到100的范围内，O/W/O乳状液和电池上游的O/W乳状液的稳定形成是可能的。电场的作用在60kVm(-1)以下相反，超过这一临界值，对流态、液滴尺寸和乳状液结构有显著影响。给出了电场强度对流型和乳状结构的影响，并对液滴尺寸进行了定量分析。给出了电场和毫米尺度通道相结合的复杂乳状液滴控制生成的结果。讨论了与文献中所报道的其他物理过程的差异。(C)2016年提交人。由爱思唯尔公司出版。
A novel approach to create O/W/O is developed and described to achieve uniform oil drop size coated with thin layers of water. Drops were created using a test cell where the DC field is applied between different internal diameter (ID) needles (from which the O/W emulsion emits upwards into a continuous oil phase) and a grounded metal ring which was located at selected distances from the needle top. The advantages compared to the previous techniques consist of possibility of control on drop size and coating layer of the water using low electric field. A high speed imaging technique has been applied to determine drop size under different flow and electric field conditions. Without the electric field, several flow regimes were observed; stable formation of both the O/W/O emulsion and the O/W emulsion upstream of the cell was possible over a range of Reynolds numbers from 80 to 100. The effect of the electric field was found to be reverse below electric field strength of 60 kV m(-1), beyond this critical value there was significant impact upon the flow regime, drop size and emulsion structure. The impact of the electric field strength upon flow pattern and emulsion structure and a quantitative analysis of droplet size are presented. The work shows the results for the controlled creation of complex emulsion droplets combining electric field and mm scale channels. The differences with the other physical processes reported in the literature are discussed. (C) 2016 The Authors. Published by Elsevier Inc.