EXPERIMENTAL INVESTIGATION OF ELECTROSTATIC SPRAY OF TWIN-FLUID ATOMIZATION

Abstract

An electrostatic atomizer of twin-fluid atomization with combined needle and annular electrode was developed, from which a relatively high speed electrostatic spray was obtained. The flow field of charged droplets of the electrostatic spray under different charging voltages was measured by the PIV technique. The characteristics of atomization and motion of droplets of uncharged and charged spray were investigated systematically and analyzed by PIV and PDA systems. The flow field of the twin-fluid jet of electrostatic spray and droplet size distribution was visualized by PIV and PDA measurement techniques. The results indicate that the flow field of spray is clearly affected by the electrical field. The velocity in the spray center becomes higher and the flow field around the spray shows a change of fluctuation with the increase of charging voltage. The diameter of spray droplets on the centerline increases when the spray is charged and keeps the trend of gradual increase from the center point to the edge of the spray. The spray expands when it is charged and the spray angle becomes difficult to define since more particles are distributed around the spray core.