Microscopic and macroscopic modeling of electrostatic-based pesticide spray systems

A microscopic model for an electrostatic spraying system is presented to investigate the effect of the voltage applied to the induction nozzle on the droplet´s charge, mobility, and charge-to-mass ratio. The variation of these parameters along the jet was also studied. The model also lays particular emphasis on the effect of the applied voltage on the spray current and the charge density at the nozzle. A macroscopic model for the electrostatic spraying system is also presented. The objective of this model is to study the spatial distribution of the droplet charge density, transit time, and trajectory in the region between the nozzle and the target in terms of the flow velocity of the spray and the space-charge-produced electric field. On the macroscopic scale, both the droplet charge density and the spray current increase with the voltage applied to the charging electrode. With the decrease of the spray flow velocity, the space-charge produced electric field becomes dominant. On the microscopic scale, induction charging eliminates the ion current from the current to the target and the associated back-ionization