Computation of ion-flow fields of AC coronating wires by charge simulation technique

Abstract

A method is developed to compute the ion flow from AC corona-discharging wire above the ground plane, without resort to simplifying assumptions. In this method, ions are emitted from the wire into the space around it when the surface gradient of the wire exceeds the onset value. The space charges are simulated by discrete line charges, and the C-S technique is used to compute the charge emission from the wire during corona periods over both the positive and negative half cycles. The simulation line charges are displaced away from and back to the wire by prevailing AC field with a subsequent recombination between the outgoing and returning line charges of opposite polarities. Among the parameters computed are: (1) the corona current components and their time variations during the positive and negative half-cycles; (2) the corona charge-voltage characteristics for different applied voltages; and (3) the corona onset and the ionization onset voltages as well as the corona ending voltage over the succeeding positive and negative half cycles. >