Numerical modeling of EHD-induced liquid extraction in a cylindrical electrode configuration

A comparison of modeling techniques for two-dimensional, adiabatic liquid extraction under an applied voltage is investigated. High voltage is applied to a central cylindrical electrode and the outer surface is grounded. The dielectric fluid is assumed to have negligible free charges and therefore only the dielectrophoretic and electrostrictive force components of the electric body force are considered. The modeling techniques compared in this paper use existing commercial code with user defined functionality to account for the interfacial forces. The main variables affecting the interfacial forces, and therefore the extraction times, are highly dependent on the treatment of the interface and the inclusion of surface tension effects. Methods which use a finite-thickness interface underestimate the interfacial force, stretch the interface and thus, overestimate of the extraction times, however these methods are currently more robust and can handle complex geometries. Methods which use a zero thickness interface result in more accurate interfacial forces but are limited to simple geometries with moderate mesh deformation and are affected by interface curvature approximation issues that affect surface tension.