Numerical Simulation of Single Droplet Hydrodynamics Affected by Electrostatic Forces with the Aid of CFD

In this study, Electrospray hydrodynamics and electrical potential dependency of heat transfer coefficient were investigated by computational fluid Dynamics (CFD). VOF method was applied to solve momentum equation of these two-phase flow and Whitaker empirical relationship for gas, liquid flow on sphere was also applied to calculate the heat transfer coefficient. The results of simulation were in accordance with experiments and showed that because of domination of surface tension by gravity and electric forces, diameter of droplets and their formation time were decreased. In addition, applying electrical potential at the velocity of 0.007 m/s has led to formation of jet and small droplets of liquid. Formation time of the droplet was decreased by increasing the velocity ten times higher than the previous time, to 0.07 m/s. By using the results of hydrodynamic simulation of droplet, convective heat transfer coefficient of droplet was calculated in various electrical potentials that showed heat transfer coefficient increased by growth of electrical potential.