Numerical Simulation of Electrostatic Jet Atomization Using VOF Method

Abstract

The atomization of a liquid jet under electrostatic field is numerically simulated using Volume-of-Fluid (VOF) method. In this phenomenon, an electrified liquid is dispersed to fine droplets by an electrostatic force acting on the charged surface of the liquid. The simulations performed in this study correspond to a transient liquid jet leaving a capillary tube maintained at a high electric potential. The Navier-Stokes equations are solved to find the velocity and pressure fields. The surface profile of the deforming jet is defined using the VOF scheme and the advection of the liquid free-surface is performed using Youngs’ algorithm. Surface tension force is treated as a body force acting on the free-surface; the method used for this purpose is the continuum surface force (CSF). To calculate the effect of the electric field on the shape of the free-surface, the electrostatic potential is solved first. Next, the surface density of the electric charge and the electric field intensity are computed, and then the electric force is calculated. Liquid is assumed to be a perfect conductor, thus the electric force only acts on the liquid free-surface; the computational method for treating this force is similar to that of the surface tension using the CSF method. The main achievement of this study is the development and validation of a method to obtain electrostatic force distribution on free surface of a conductive fluid and integration of this method into the VOF scheme in order to predict the behavior of the flows with free surface under the effect of an electric field.