Mathematical modeling of the combined corona-electrostatic field of roll-type separators

Corona and induction charging mechanisms are frequently associated in modern roll-type electrostatic separators. Various electrode configurations have been proposed and numerous attempts have been made in order to fully-characterize them. This paper approaches this problem from a computational point of view. The boundary element method is employed for analyzing the electrostatic 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 uniformity of the electric field near the ionizing element and at the surface of the grounded rotating rod electrode. These data can be used by the designer 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 paved the way for an original algorithm for the computation of the electric field distribution in the presence of the space charge generated by the corona electrodes.