The present work is to examine the effect of the electric charging on the deposition efficiency of spray drops on a flat metal(copper) plate under an electrostatic field. The spray flow was visualized and the amount of the liquid deposited on the flat metal plate was measured. At the same time trajectories of the spray drops were calculated numerically to confirm the flow behavior.
Spray deposition efficiency increased with the higher voltage applied to the atomizer for a fixed liquid flow rate. This is because the electrically changed drops tend to follow the electric-field lines toward the plate, and the effects of the gravity and the motion of the entrained air become minor with the higher voltage input. Also, the momentum of drops prior to collision becomes larger by attraction force between the drops and the plate. Hence the number of the bouncing drops without breaking (by the wall collision) decrease and more drops are disintegrated into smaller ones. Thereby, once the spray drops reach the plate, those tend to remain attached on the surface.
