ICLASS 97
Proceedings of the Seventh International Conference on Liquid Atomization and Spray Systems

ISBN Print: 89-950039-2-8

Prediction of the Effect of Electrostatic Charging on Spray Characteristics

DOI: 10.1615/ICLASS-97.780
pages 633-640

Abstract

The effect of electrostatic charging on spray characteristics has been numerically investigated. The governing equations for mass, momentum, and energy have been solved numerically using an Arbitrary Lagrangian Eulerian (ALE} grid. The turbulence has been solved using the k-ε. model for turbulence. A term for pseudo viscosity is added to the momentum equations to include the effect of the spray droplets on both turbulence generation and destruction. The effect of droplets interaction on the drag coefficient has been considered. Both the droplets collision and breakup are considered. Regarding the electrostatic charging, it has been expressed in the equations through its impact on the droplet effective surface tension and the repulsion forces between droplets. The effective surface tension is considered in the droplet breakup model, originally developed to account the effect of aerodynamic forces. The liquid was assumed to be conductive and charged by conduction. The results showed that charging the spray droplets enhances the droplet breakup with an increase in spray volume due to the repulsion forces between the spray droplets. Increasing the charging voltage up to 2.5 kV resulted in increasing both the spray half cone angle and the penetration time by about 6 times and 20 percent respectively. Also, the spray droplet size distribution showed a shift toward smaller droplet sizes as the electrostatic charging voltage increases.