MODELING OF CONDUCTIVE PARTICLE BEHAVIOR IN INSULATING FLUIDS AFFECTED BY DC ELECTRIC-FIELDS

Several electrostatic technologies, such as separation of granular mix tures, flocking, printing, or biological cell manipulation, are based on tile accurate control of conductive particle motion in insulating g ases or liquids by means of relatively high de electric fields, This p aper aimed at characterizing the behavior of such particles by numeric al modeling of two aspects: 1) particle motion under the action of ele ctric field forces and 2) insulation breakdown triggered by mobile par ticles, The equations of particle motion were written by taking into a ccount both gravitational and drag forces, as well as the rebound at p article impact with the electrodes. If the particles move in ionized a ir, their charge varies in rime. In that case, the equation of particl e charge should be added to the mathematical model, The output data of the programs for numerical simulation of particle behavior are ins go od agreement with the available experimental results, Particle movemen ts were shown to be influenced by the intensity of the electric field, by the density of the space charge, by size and mass density of the p articles, as well as bg their coefficient of restitution at impact wit h the electrodes, The conclusions regarding the behavior of conductive particles in insulating fluids are useful for the development of impr oved electrostatic separation technologies; they are of particular int erest to all manufacturers of high-voltage equipment.