Experimental Investigation of Electrostatic Dispersion of Nonconductive Fluids into Conductive Fluids

Abstract

Electrostatic dispersion has been used extensively in many fields including electrostatic printing, paint spraying, crop spraying, and chemical processing. Most of the applications reported to date, however, are limited to spraying fluids of high electrical conductivity into fluids of lower electrical conductivity. Recent attempts on electrostatic spraying of nonconductive fluids into conductive fluids have shown promising results. Here, the authors report an experimental investigation of the influence of physical properties of the fluids, nozzle geometry, and operating conditions on the spraying behavior of nonconductive fluids into conductive fluids. Results show that the experiments are consistent with the theory of electrohydrodynamics. Also, the results provided in this paper can lead to effective nozzle design for gas-liquid and liquid-liquid dispersions for various applications. A particular example of its application in the chemical industry is solvent extraction, where the objective is to enhance the surface area of contact between the solvents and internal mixing within the drops to increase the mass-transfer rate and the separation efficiency. Devices traditionally used to contact two phases make use of mechanical agitation with various types of impellers. These devices waste a large fraction of the agitation energy in excessive mixing of the continuous phase.