On the Influence of Hydrodynamic and Electric Forces on the Film Drainage Between Two Rising Drops in a Liquid/Liquid System

摘要

In this paper, the rise of two drops of n-butanol in quiescent water under the influence of buoyancy force with and without the application of electrical attraction force has been examined. The 2D numerical model proposed in this work is based on an Arbitrary-Lagrangian-Eulerian method ALE (moving mesh) for capturing interfaces, coupled with Navier-Stokes equations for the fluid flow, then the resulting system of equations is solved by the finite elements commercial software Comsol Multiphysics 4.2a. The numerical approach has been firstly validated with the existing results for the rise of a single n-butanol drop in water and for the coalescence of two water drops in stagnant polybutene oil under the action of an electric field. Thereafter, the study has been extended to the rise of two n-butanol drops in water under a buoyancy force with and without the electric field. Some focus has been given on the influence of the distance between the drops on their rising velocities and on the film drainage between the two drops. Subsequently, the influence of the applied electrical field strength on the liquid film drainage has been investigated. It has been found out that the application of the electrical field generates an attractive force, which provokes an acceleration of the drainage between the two drops. Copyright ~C 2019 Praise Worthy Prize S.r.l. - All rights reserved.