Experimental study of electrostatic spray modes of high-flowrate water with horizontal nozzle

Abstract

Since the introduction of electrostatic spray technology for several decades, it has been configured most frequently with a vertical discharge nozzle. With a recent expansion in application areas, electrostatic spray with a horizontal nozzle has been studied in a narrow range of low volumetric flowrates. In this study, a horizontal discharge nozzle with an upright collector plate is experimented in consideration of its application to electrostatic precipitators. Using a large volumetric flowrate at the scale of milliliters per minute, the operation modes with horizontal nozzle are observed with high-speed digital cameras under different test conditions of nozzle sizes, nozzle-to-plate distances, and volumetric flowrates. The operation modes were classified and compared with the conventional electrostatic spraying modes. From the experiment, it is found that the nozzle diameter and the volumetric flowrate influence the spraying pattern while the applied voltage and nozzle-to-plate distance have a more defined impact on the determination of the modes. A novel spray map diagram was provided according to Reynolds number and electric field intensity. This diagram will serve to predict which modes will occur at certain geometric and flowrate conditions.