COMPUTATIONAL MODELLING OF ELECTROHYDRODYNAMIC ATOMIZATION

Abstract

Electrohydrodynamic atomization [EHDA] of liquids is a transport phenomenon, whichdescribes the motion of the liquids subjected to electric field. The atomization occurs froma steady conical meniscus called Taylor cone that is the result of the balance of the electricalnormal stress and the surface tension. As a consequence of the electric field the surfacecharged in the Taylor cone is accelerated towards the cone apex. Subsequently, due to thisacceleration a jet with a high charge density is formed at the cone apex. Finally, the jetbreaks-up into a line of charged drops which open up into a spray.In order to complement the experimental and analytical area, in the present study we proposea numerical solver for EHDA using volume of fluid. The solver is able to compute thedroplet formation, velocity and electric field using OpenFoam.The numerical simulation was approached from two perspectives; First, a drop is suspendedin a viscous liquid under the influence of external electric field, applied by two electrodeslocated at the top and bottom of the computational domain. The drop is located in the middleof the two electrodes. Finally, the cone-jet starting from the emitter up to the extractor electrode.The voltage is applied in the emitter. The liquids are modelled as an incompressiblefluid with constant conductivity. The electrostatic part have been simplified by employingthe perfect dielectric model and leaky dielectric model. The results are compared with theexperimental data for polar (ε ≫1) and nonpolar (ε < 10) liquids.

Date of Award	1 Aug 2015
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Alistair Revell (Supervisor) & Katharine Smith (Supervisor)