Experimental Investigation on Droplet Deformation and Breakup under Uniform DC Electric Field

Abstract

In order to understand the dynamic behaviors of the charged water droplet in the presence of electric field, the experimental investigation is conducted in this paper. A uniform DC electric field is produced by applying high voltage between two parallel copper plates which are placed horizontally in a silicon oil tank. The variation range of the electric field intensity is 0–6.67 kV/cm. Under the influence of the electric field, deformation, motion, breakup and other dynamic behaviors of the charged water droplet with the initial diameter of 5.36 mm are observed and analyzed. Results show that the increase in the electric field intensity results in the elongation of the charged droplet. When the electric field intensity increases to 2.5 kV/cm and 3.0 kV/cm, the droplet would deform into an unstable Taylor cone shape, and then the top of droplet breaks up into some daughter droplets. These daughter droplets move up and down between two copper plates. Further increasing the electric field intensity to 3.67 kV/cm, some of daughter droplets forms a liquid bridge linked the two plates which likes a pearl chain, and then discharge phenomenon occurs. For the enormous electric field intensity of 6.67 kV/cm, numerous tiny droplets, which distribute uniformly in the silicon oil, are produced by the breakup of larger daughter droplets and the large droplet located on the lower plate. This research has certain application value in the fields of oil treatment, electric demulsification and so on.