Forces acting on water droplets falling in oil under the influence of an electric field: numerical predictions versus experimental observations

Experimental study of electrocoalescence of water drops in crude oil using near-infrared camera

“…However, for coalescence between two drops with an imposed electric field, the electric charge distributions on the drop interfaces and the subsequent electric forces play the major role. The attraction force between the drops can become very large as they approach one another (Atten 1993;Davis 1964;Chiesa et al 2005); moreover, the electrostatic pressure at the interfaces can significantly affect the drop shape and, even, trigger surface instability (Atten and Aitken 2010;Latham and Roxburgh 1966). It has been proposed that such a surface instability generates a water bridge between the drops that finally results in the drop merging (Lundgaard et al 2006).…”

Simulation of turbulent electrocoalescence

“…The dipoleinduced-dipole (DID) model of Siu et al (2001) is computationally efficient and suited for multi-droplet systems. Chiesa et al (2005) showed that the DID model was superior to the point-dipole model at small droplet spacings. The DID model is written as…”

“…Expressions valid for rigid spheres are therefore used to model the drag force in this work. Chiesa et al (2005) studied forces between two water droplets under the influence of an electric field and recommended expressions for the different forces. The expressions given below for the film-thinning and dipole-dipole forces that were suggested by Chiesa et al are used in the present work.…”

Stable deformation of droplets surface subjected to a high-voltage electric field in oil

“…The digital oscilloscope belongs to the Tek series and was employed to conduct real-time correction of the output voltage of the power supply. To avoiding static charge transfer from glass to droplet, the micro syringe needed to be coated with gold and grounded, as Chiesa's experiment [24]. Several pieces of glassware and a cleaning instrument were also utilised.…”