SF_6/N_2混合气体放电过程的PIC/MCC仿真模拟

PIC/MCC Simulation of Gas Discharge Process in SF_6/N_2 Gas Mixture

为了研究SF_6/N_2混合气体中圆柱形绝缘子的放电过程,采用粒子网格法(PIC法)与蒙特卡罗碰撞模型(MCC模型)相结合的方法 (PIC/MCC法)仿真模拟了放电过程中带电粒子的运动轨迹,同时充分考虑了电子与SF_6分子及N_2分子的各种电离碰撞过程以及复合过程。仿真结果表明:放电过程中,电子主要与SF_6分子发生电离碰撞过程以及复合过程。放电过程初始阶段,空间电子数呈现出上下波动的规律,当t≥20 ns时,空间电子数将迅速减少直至完全复合。此外,在整个放电过程中,正离子分布范围始终大于负离子分布范围。PIC/MCC仿真模拟从纯微观角度展现了SF_6/N_2混合气体放电过程,对研究SF_6/N_2混合气体放电过程具有重要意义。

In order to study the discharge process of a cylindrical insulator placed in SF6/N2 gas mixture, a method that combines the particle-in-cell method （PIC method） and Monte Carlo collision model （MCC model） has been developed to model the trajectories of charged particles during a discharge process with consideration of the collisional ionization and recombination processes between electrons and SF6/N2 molecules. Results show that the main ionization and recombination processes are those between electrons and SF6 molecules. At the initial stage of the discharge process, the number of electrons exhibits regular fluctuation. After 20 ns, the electron number decreases quickly until complete recombination. In addition, the space over which positive ions distribute is always larger than that for the negative ions in the whole discharge process. The PIC/MCC model illustrates the discharge process of SF6/N2 mixture at microscopic level and has significant implication for the study of SF6/N2 mixture discharge process.