Motion and Deformation of a Water Droplet Under the Influence of an Electric Field

Author(s):  
Kyle DeProw ◽  
Jeff Darabi

Due to its molecular polarity, a water droplet suspended in a dielectric medium experiences a force under the influence of an electric field. However, unlike a charged rigid particle, a water droplet undergoes a significant deformation due to its liquid state. Thus, the dynamic behavior of the water droplet cannot be fully analyzed without accounting for the interaction between the electric and fluid fields. In an effort to broaden our understanding of this phenomenon, a parallel plate electrode system was constructed inside a glass chamber. A water droplet was suspended in the glass chamber filled with insulated oil. After applying a high voltage across the plates, the droplet motion was recorded with a camera and analyzed using an image processing program. The effects of several parameters including, droplet size, droplet conductivity, and initial droplet position were investigated. Results obtained from this investigation help gain a better understanding of the droplet deformation and breakup mechanisms spanning several fields, some of which include oil-water separation, electrocoalescence, and electrospraying.

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1733
Author(s):  
Yi Shi ◽  
Jiaqing Chen ◽  
Zehao Pan

As most of the light and easy oil fields have been produced or are nearing their end-life, the emulsion stability is enhanced and water cut is increasing in produced fluid which have brought challenges to oil–water separation in onshore and offshore production trains. The conventional solution to these challenges includes a combination of higher chemical dosages, larger vessels and more separation stages, which often demands increased energy consumption, higher operating costs and larger space for the production facility. It is not always feasible to address the issues by conventional means, especially for the separation process on offshore platforms. Electrostatic coalescence is an effective method to achieve demulsification and accelerate the oil–water separation process. In this paper, a novel compact electrostatic coalescer with helical electrodes was developed and its performance on treatment of water-in-oil emulsions was investigated by experiments. Focused beam reflectance measurement (FBRM) was used to make real-time online measurements of water droplet sizes in the emulsion. The average water droplet diameters and number of droplets within a certain size range are set as indicators for evaluating the effect of coalescence. We investigated the effect of electric field strength, frequency, water content and fluid velocity on the performance of coalescence. The experimental results showed that increasing the electric field strength could obviously contribute to the growth of small water droplets and coalescence. The extreme value of electric field strength achieved in the high-frequency electric field was much higher than that in the power-frequency (50 Hz) electric field, which can better promote the growth of water droplets. The initial average diameters of water droplets increase with higher water content. The rate of increment in the electric field was also increased. Its performance was compared with that of the plate electrodes to further verify the advantages of enhancing electrostatic coalescence and demulsification with helical electrodes. The research results can provide guidance for the optimization and performance improvement of a compact electrocoalescer.


RSC Advances ◽  
2015 ◽  
Vol 5 (66) ◽  
pp. 53802-53808 ◽  
Author(s):  
Jian Li ◽  
Long Yan ◽  
Haoyu Li ◽  
Jianping Li ◽  
Fei Zha ◽  
...  

Superhydrophobic attapulgite coated mesh was used to separate oil/water mixtures efficiently. Besides, the separation mechanism was elaborated by interpreting the different states of water droplet on the surface before and during separation.


Nanoscale ◽  
2021 ◽  
Author(s):  
Weihao Pan ◽  
Song Wu ◽  
Liu Huang ◽  
Jinlong Song

Superhydrophobic micro-conical pillar arrays have huge application prospects, from anti-icing to oil/water separation, corrosion resistance, and water droplet manipulation. However, there is still a lack of versatile methods with high...


2018 ◽  
Vol 10 (4) ◽  
pp. 4213-4221 ◽  
Author(s):  
Xiaojing Su ◽  
Hongqiang Li ◽  
Xuejun Lai ◽  
Lin Zhang ◽  
Xiaofeng Liao ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Yaming Zhang ◽  
Changjiang Ding ◽  
Jiabao Ni ◽  
Zhiqing Song ◽  
Rui Zhao

In order to investigate the thawing time and water-holding capacity under high-voltage electric field (HVEF), we studied the thawing experiments of frozen beef in a multiple needles-to-plate electrode system. The electric field, thawing characteristics, and quality parameters during the thawing process were measured. The results showed that compared with the control, the thawing time of beef under HVEF was significantly shortened, the thawing rate increased significantly, the drip loss decreased, and the centrifugal loss increased during the thawing process. By the response surface analysis and single-factor analysis of variance, the best thawing conditions for each thawing parameter were determined. It provides a theoretical basis and practical guidance for understanding the characteristic parameters of the high-voltage electric field thawing technology.


Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 778 ◽  
Author(s):  
Jie Liu ◽  
Sheng Liu

Droplet microfluidic technology achieves precise manipulation of droplet behaviors by designing and controlling the flow and interaction of various incompatible fluids. The electric field provides a non-contact, pollution-free, designable and promising method for droplet microfluidics. Since the droplet behaviors in many industrial and biological applications occur on the contact surface and the properties of droplets and the surrounding environment are not consistent, it is essential to understand fundamentally the sessile droplet motion and deformation under various conditions. This paper reports a technique using the pin-plate electrode to generate non-uniform dielectrophoresis (DEP) force to control sessile droplets on hydrophobic surfaces. The electrohydrodynamics phenomena of the droplet motion and deformation are simulated using the phase-field method. It is found that the droplet moves along the substrate surface to the direction of higher electric field strength, and is accompanied with a certain offset displacement. In addition, the effect of pin electric potentials, surface contact angles and droplet volumes on the droplet motion and deformation are also studied and compared. The results show that higher potentials, more hydrophobic surfaces and larger droplet volumes exhibit greater droplet horizontal displacement and offset displacement. But for the droplet vertical displacement, it is found that during the first revert process, the release of the surface tension can make the droplet with low potentials, small contact angles or small droplet volumes span from negative to positive. These results will be helpful for future operations encountered in sessile droplets under non-uniform electric fields towards the droplet microfluidics applications.


2016 ◽  
Vol 3 (18) ◽  
pp. 1600461 ◽  
Author(s):  
Xi Zheng ◽  
Zhenyan Guo ◽  
Dongliang Tian ◽  
Xiaofang Zhang ◽  
Lei Jiang

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