Maximum deformation of charged dielectric droplets

Abstract

In this study, the maximum deformation of micrometer sized droplet of dielectric water-based paint impact onto a flat steel surface and exposed to a constant and uniform electric field was investigated by simulation based on the level-set method within the framework of Navier-Stokes. Upon a series experiments for droplet impacting and spreading of water-based paint on dielectric solid substrate with different initial impacting velocities in external electric field, results demonstrated that the maximum deformation ratio increases with the increase of initial impacting velocity, and can scale as We1/4 where We is the Weber number. The effect of electric field intensity to the final shape of droplet of water-based paint on a hydrophobic surface was investigated. It was found that the eccentricity of droplet can scale as E where E is the electric field intensity, and a prediction model of droplet between the deformation ratio (ζF) of droplet at final equilibrium contact angle and E was presented. Finally, the effect of applied voltage and equilibrium contact angle was studied.