ELECTRICAL AND SPRAY CHARACTERISTICS OF A MULTIORIFICE CHARGE-INJECTION ATOMIZER ELECTRICALLY INSULATING LIQUIDS

Electrostatic atomization of electrically insulating liquids has a number of potential uses with respect to combustion applications and the food processing industry. For charge-injection atomizers that generate well-dispersed spray plumes of this class of liquids, spray-specific charge is inextricably linked to the orifice diameter such that the product of these two variables is approximately constant. This, for a single-orifice atomizer, constrains the maximum flow rate against the mean spray drop diameter for a given pressure drop and spray-specific charge. A relaxation of this requirement is possible using a novel evolution of the high-voltage (HV) emitter electrode surface, permitting an orifice array to be used. This permits high spray charge densities at high flow rates without the precision alignment issues that face charge-injection atomizers that possess a pointed high-voltage electrode. Results show that current-voltage characteristics are very similar to a point-plane system, and both electrical and spray measurements revealed that the multiorifice atomizer is able to provide finely atomized jets even though there is a slight degradation in spray performance when introducing more holes.