CFD INVESTIGATION OF TWO-PHASE FLOW ELECTROHYDRODYNAMIC ATOMIZATION OF THE TAYLOR CONE AND LIQUID JET PRIMARY BREAKUP USING THE VOLUME OF FLUID METHOD

Electrohydrodynamic atomization or electrospray is a multiphase and multiphysics fluid flow. Uniform distribution of generated droplets after the liquid jet's primary breakup, generation of finer droplets, and more control over determining the droplets' size in the primary breakup are its advantages. By considering the electric field-flow rate diagram, which is called the stability island, the volume of fluid method and the continuous surface force model were used to capture the interface and calculate the surface tension force of the Taylor cone, respectively. This study is simulated in OpenFOAM by applying the different electric potentials, various nozzle-collector distances, and different liquid flow rates. The results reveal that increasing the electric potential strength and reducing the nozzle-collector distance lead to more electrical stresses caused by the electric potential gradient on the interface. Surface tension force, gravity, electric polarization stress, viscosity stress, normal electric stress, and tangential electric stress applied to the liquid lead to forming the Taylor cone. Therefore, the liquid is pushed towards the apex of the Taylor cone, the velocity increases near the cone's tip, a liquid jet with a smaller diameter is formed, and the liquid jet is broken into droplets. Raising the Reynolds and Weber numbers increases the polarization force and reduces the surface tension force of the liquid-air interface. Finally, by comparing the changes of the surface tension force applied to the interface at each step of increasing Re and We, we predict that it will behave independently for numbers greater than Re=88 and We=1.