SCI和EI收录∣中国化工学会会刊

›› 2016, Vol. 24 ›› Issue (9): 1147-1153.

• Separation Science and Engineering • 上一篇    下一篇

Coalescence behaviour of water droplets in water-oil interface under pulsatile electric fields

Morteza Hosseini   

  1. Faculty of chemical engineering, Babol Noshirvani University of Technology, Babol, Iran
  • 收稿日期:2015-09-24 修回日期:2016-03-01 出版日期:2016-09-28 发布日期:2016-11-11
  • 通讯作者: Morteza Hosseini,E-mail address:mortezh@yahoo.de

Coalescence behaviour of water droplets in water-oil interface under pulsatile electric fields

Morteza Hosseini   

  1. Faculty of chemical engineering, Babol Noshirvani University of Technology, Babol, Iran
  • Received:2015-09-24 Revised:2016-03-01 Online:2016-09-28 Published:2016-11-11

摘要: In this research, the deformation of water droplets in sunflower oil-interface under pulsatile electric field was studied experimentally. Three types of coalescence were observed:(i) complete coalescence, (ii) incomplete coalescence and (iii) no-coalescence. The first type is desirable because of leaving no secondary droplets. The second type that produced secondary droplets which caused by necking process, due to extreme elongation of droplets (mostly small droplets), was undesirable; because the small droplets were more difficult to coalesce and remove. The no-coalescence was caused by very fast coalescence and extensive pushing of droplet into the continuous phase. In this work the process was operated with the utilization of a batch cylindrical separator with high voltage system. The lower part of the cylinder was filled with the aqueous phase and its top part was filled with sunflower oil to form an interface between the two phases. The effects of electric field strength, frequency, and waveform types were investigated. It was found that, the ramp-ac waveform was the best waveform, avoiding the production of secondary droplets and in this case the frequency also played an important role.

关键词: Drop-interface coalescence, Drops deformation, Non-uniform electric field, Di-electrophoresis, Pulsatile electric field

Abstract: In this research, the deformation of water droplets in sunflower oil-interface under pulsatile electric field was studied experimentally. Three types of coalescence were observed:(i) complete coalescence, (ii) incomplete coalescence and (iii) no-coalescence. The first type is desirable because of leaving no secondary droplets. The second type that produced secondary droplets which caused by necking process, due to extreme elongation of droplets (mostly small droplets), was undesirable; because the small droplets were more difficult to coalesce and remove. The no-coalescence was caused by very fast coalescence and extensive pushing of droplet into the continuous phase. In this work the process was operated with the utilization of a batch cylindrical separator with high voltage system. The lower part of the cylinder was filled with the aqueous phase and its top part was filled with sunflower oil to form an interface between the two phases. The effects of electric field strength, frequency, and waveform types were investigated. It was found that, the ramp-ac waveform was the best waveform, avoiding the production of secondary droplets and in this case the frequency also played an important role.

Key words: Drop-interface coalescence, Drops deformation, Non-uniform electric field, Di-electrophoresis, Pulsatile electric field

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