Post-dispersion electrification of droplets in a system with pneumatic atomization

Abstract

The process of electrifying aerosol particles dispersed by a pneumatic sprayer with supersonic air flow is presented. To avoid the electric-field shielding effect, confirmed by investigations of induction charging of aerosol droplets with application of a concentric induction electrode placed in the region of liquid dispersion, the droplet electrification process following the dispersion of liquid was proposed. The supersonic atomizing head was equipped with an external high voltage contact electrode placed concentrically and perpendicularly to the droplets stream and closely to the atomizing head. Experiments were conducted in air, at ambient conditions (T = 18±2 °C, RH = 55±3%), for standard air feeding rate (0.5 m3/min, 0.4 MPa) and regulated dispersed liquid rate (0.1 – 0.55 l/min). Results of the applied electrification process, characterized by a (Q/m) factor measured as a function of liquid feed rate, have shown that the (Q/m) values achieved for post-dispersion electrification are comparable to the values obtained for typical induction electrification with application of a concentric electrode.