Premises for the mathematical modeling of the combined corona-electrostatic field of roll-type separators

Corona and induction charging mechanisms are frequently associated in moder n roll-type electrostatic separators; Various electrode configurations have been proposed and numerous attempts have been made in order to fully chara cterize them; This paper approaches this problem from a computational point of view, The boundary-element method is employed for analyzing the electro static field distribution generated by a typical arrangement, consisting of a wire-type corona electrode and an ellipse-profile nonionizing electrode, The computed results pointed out the effect of various parameters on the u niformity of the eleetric:field near the ionizing element and at the surfac e of the grounded;rotating roll electrode. These data can be used by the de signer in order to improve the electrode configuration, produce a, uniform field in the active zone of the separator, and reduce the corona inception voltage. At the same time, they validate two important premises for the mat hematical modeling of the combined corona-electrostatic field of a roll-typ e separator: 1) Peek's law can be used for evaluating the electric field st rength at the surface of the wire electrode at corona onset in any of the u sual electrode configurations and 2) the distribution of the electric field in-the;active zone of the separator is affected only by the geometry of th e high-voltage electrode system.