Modelling of corona discharge of a tri-electrode system for electrostatic separation processes

The study presents a detailed experimental and numerical analysis of the corona characteristics of a proposed `tri-electrode system´ for electrostatic separation applications. The system consists of an ionising wire, a movable auxiliary wire and a non-ionising cylinder, having the same voltage and placed parallel above a grounded plate. A computational technique coupling the method of characteristics and the charge simulation method is developed to model the corona governing equations of the proposed configuration. Influence of the auxiliary wire´s position on field modulation of the ionising wire, corona onset and switching on/off of the discharge is established both numerically and experimentally. Dependence of the spatial distributions of the electric field and current density on the system´s geometrical characteristics is evaluated and assessed. The study includes a physical model of the corona discharge of this particular electrode arrangement and demonstrates the configuration´s specific features and advantages as compared with the earlier designs. The computed results compared favourably well with experiments.