FEM Simulation of Charge Accumulation Behaviours on Polyimide Surface in 10 kV Negative High-Voltage Corona Polarization Process

Abstract

The study investigates behaviors of charge accumulation on an insulated surface from micro perspective via the numerical method. A coupling bridge between the micro-ion reaction system and the macroscopic multi-physical field was constructed by means of the electronic energy distribution function, which revealed the coupling mechanism in the process of corona charge. Moreover, it revealed the transport and accumulation mechanism of charge on the surface of insulating materials. 2D axisymmetric finite element model was built based on the multi-physical field coupling theory. 10 kV negative voltage was applied using a pin-plate electrode structure and polyimide film was taken as insulated surface to simulate the dynamic charge accumulation behaviors in the corona discharge process. The generation, migration and distribution laws of charged ions and electrons in different stages of corona discharge process were given. Charge distribution laws in different stages of charge process of polyimide were given and discussed. When corona discharge reached quasi-stationary state, the total charge number accumulated on the surface was at 10-10 Coulomb order of magnitude, and the drift current was at 10-7 ampere order of magnitude. An experimental platform was set up to test drift current and charge distribution under quasi-stable discharge state. The results show that the simulation results and the experimental data under quasi-stable state are consistent, thus indirectly verifying the correctness of the proposed numerical simulation algorithm and its simulation results.

Keywords

• Air gaps
• charge transfer
• finite element methods
• surface charging