Numerical Simulation of Highly Charged Droplets Dynamics with Primary Break-up in Electrospray at Sub Rayleigh Limit

Authors

1 Combustion and Propulsion Laboratory, Faculty of Aerospace Engineering, K.N. Toosi University of Technology, Tehran, Iran

2 Department of Aerospace Engineering, K.N. Toosi University of Technology, Tehran, Iran

Abstract

The size and the axial and radial velocity distributions of electrically controlled droplets generated from Taylor cone operating in the stable cone-jet regime are simulated by numerical modeling of electrosprays. A model is formulated as function of liquid flow rate, needle-to-counter electrode distance, applied voltage, and electrical conductivity and surface tension of the liquid in a DC electric field is presented with a 2D electrohydrodynamic model. The droplet size reduction can be explained by evaporation and/or Coulomb explosion. Results show that moving downstream, the average velocity of droplets decreases monotonically. This paper reports a numerical study of the effects of an externally applied electric field on the dynamics of drop formation from a vertical metal capillary. The fluid issuing out of the capillary is a viscous liquid, the surrounding ambient fluid is air, and the electric field is generated by establishing a potential difference between the capillary and a horizontal, electrode placed downstream of the capillary outlet. The Primary jet Break-up and droplet transport and evaporation of electrohydrodynamic sprays is investigated by modeling of droplet size and velocity distribution in spray cones and a series of drop migrations under the influence of an electric field were carried out and the results are in good agreement with other theoretical and experimental studies.

Keywords