Induction charging of water spray produced by pressure atomizer

Charged sprays are widely used in various branches of industry, for example, for surface coating or gas cleaning by wet electrostatic scrubbers. The selection of appropriate system for charged spray generation is of crucial importance for obtaining high cleaning efficiency of a scrubber. This paper presents comparative experimental studies of parameters of charged sprays produced by various types of pressure atomizers with charging of droplets by induction, using three types of induction electrodes. The spray systems were characterized in terms of droplet size distribution and specific electric charge carried by the generated droplets. The induction charging process was investigated experimentally for the following parameters: voltage of induction electrode, inter-electrode distance, supply water pressure. It was determined that nozzles of lower flow rate generate sprays of higher specific charge, because the Sauter Mean Diameter for these nozzles is smaller. It was also found that the specific charge of droplets increases with increasing voltage applied to the induction electrode, but only to a certain voltage magnitude. Above this voltage level, the specific charge decreases due mainly to the shielding effect of space charge of produced droplets and the corona discharge from induction electrode, which neutralizes the droplets' current. It was shown that the specific charge of droplets decreases with increasing Sauter Mean Diameter of those droplets. (C) 2019 Elsevier Ltd. All rights reserved.