Simulation Study on Ellipsoidal Electrode Negative Corona Discharge in Ring Mode

The corona discharge phenomenon has been of great interest, and it is widely used in practical applications. By coupling the fluid dynamics equations and the Poisson equation, the negative corona discharge between <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</i> plane and an ellipsoidal electrode is modeled in this article. The mechanism of ring mode discharge is, for the first time, systematically investigated through numerical simulation. The relationship between the mode of first discharge and electrode-plane setup conditions, such as various cathode shapes, applied voltages, and gap distances, is analyzed. The position where ring mode discharge occurs is correlated with the maximal electric field intensity during the discharge, which is generated by a combination of boundary charge and volume charge in the domain. It is found that in some cases, the discharge pulses can all be in ring mode. The first discharge tends to be in ring mode when the absolute value of applied voltage is lower, the semiaxis ratio <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$a/b$</tex-math> </inline-formula> is larger, or the gap distance is longer. This study provides important insights for optimizing the design of electrodes and improving the efficiency of discharge in applications such as electrostatic precipitators, plasma devices, aero-engines, and other devices utilizing corona discharge.