Experimental and numerical investigations of DC corona discharge in the triode system

One practical application of corona discharge is the electrostatic charging of insulating materials to confer specific electrical properties. The “triode” electrode system is then frequently used to direct and control the charge level. The aim of this article is to characterize numerically and experimentally this electrode arrangement in order to optimize the charging process. In the present work, an innovative grid consisting of a set of parallel wires was utilized. The geometry of this new grid facilitated a numerical investigation of corona discharge in the triode configuration by employing a 2D simulation performed in COMSOL Multiphysics software. The study explores the effect of variation of different parameters such as wire-to-plane distance, grid-to-plane spacing, inter-wire gap of the grid, applied voltage polarity and grid potential. It was found that the introduction of the grid into the inter-electrode space, as well as the variation of its various parameters, has a considerable impact on the discharge characteristics, modifying both the amplitude and the shape of the electric field and space charge on the ground plane. The results also show a satisfactory correlation between experimental and simulation values, confirming the validity of the numerical model with the new grid.