Inception of corona discharges in typical electrode configurations for electrostatic processes applications

The corona inception electric field at the surface of a wire electrode is usually evaluated by an empirical formula established by Peek. That formula was found to be valid in several simple electrode configurations (wire-cylinder, wire-plate), which are typical to electrostatic precipitators. The aim of this paper is to extend the study to other situations encountered in electrostatic applications. The experimental setup specifically modeled the several electrode arrangements which are commonly used with roll-type electrostatic separators. It consisted of several types of corona electrodes, connected to a regulated DC high-voltage supply, and a rotating roll electrode, with an embedded current probe, connected to the ground. The effect of associating the corona wire to one or several tubular electrodes of various shapes and sizes was investigated. The experimentally-determined corona inception voltage was used as input data of a boundary element method program for the electric field computation. The computed values of the electric field were compared with those given by Peek´s formula for wire electrodes of same radius. The derived conclusions can be of help in the custom design of the corona electrode arrangements for various electrostatic applications