阴极曲率半径对微米尺度气隙击穿的影响规律研究  

Study on the Influence of Cathode Radius on the Breakdown Characteristics across Microgaps in Air

作　　者：常泽洲 孟国栋[1] 应琪 成永红[1] Chang Zezhou;Meng Guodong;Ying Qi;Cheng Yonghong(Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiao Tong University,Xi’an 710049 China)

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,西安710049

出　　处：《电工技术学报》2023年第4期1032-1041,共10页Transactions of China Electrotechnical Society

摘　　要：微米尺度气隙击穿特性研究对微结构绝缘性能评价和微放电等离子体应用具有重要意义。该文建立了微米气隙击穿的二维物理模型,利用粒子模拟/蒙特卡洛碰撞(PIC/MCC)方法开展微米气隙击穿过程中电场分布及带电粒子的仿真研究,得到阴极的曲率半径对于微米气隙电场分布、带电粒子分布以及击穿路径的影响规律,并结合实验结果对仿真结果进行了验证,最后讨论分析极不均匀场下微米空气气隙击穿物理过程。结果表明,阴极曲率半径R_(0)对微米尺度击穿特性的影响规律主要分为两个阶段:当R_(0)<5μm时曲率半径的变化对电场畸变的影响较大,进而导致击穿电压变化较大;当R_(0)>5μm时R_(0)对电场畸变的影响逐渐变小,对击穿电压影响减弱。当间隙距离d为5μm时阴极场发射电流占总电流的95%以上,证明了场致电子发射成为击穿的主导机制。同时,阴极表面的放电区域面积随曲率半径的增加而增大,进而导致击穿电流增大。研究结果有助于进一步分析和理解微米尺度击穿过程的影响因素及其微观作用机制。The characteristics and mechanism of microgap breakdown is of great significance to the insulation reliability evaluation of micro devices and plasma generation at this dimension. Based on the theory of micro-scale breakdown, field electron emission and secondary electron emission are two major cathode emission processes which may dominate the breakdown at microscale. Therefore, exploring the role of the cathode in the process of micron breakdown and further understanding the mechanism of micron-scale breakdown are very vital to the evaluation of electrical insulation performance and the application of microplasma. To address these issues,a two-dimensional physical model of microgap breakdown in air is established, and the numerical simulation on electric field distribution and charged particles in the process of microgap breakdown in air is carried out by using particle in cell/Monte Carlo collision(PIC/MCC) method, which are also verified by the experimental results.Firstly, based on the experimental setup, a two-dimensional physical model of microgap breakdown in air is established. Secondly, with the aid of Vsim software, numerical simulation of microgap breakdown is carried out by using PIC/MCC method. Simulation results of electric field distribution characteristics show that the field enhancement factor β decreases from 2.50 to 1.65 when the cathode radius R_(0)increases from 1μm to 10μm. It indicates that the local electric field distortion on the cathode surface decreases, and the field emission threshold voltage increases with the increase of the cathode radius. A larger voltage is demanded for the field electron emission, so the breakdown voltage gradually increases. Simulation results on current variation characteristics during breakdown show that field emission current accounts for more than 95 % of anode current, which means field emission dominates the breakdown process. Moreover, the amplitude of the field emission current is proportional to the radius of the cathode. When R_(0)increases from 1

关 键 词：微米间隙击穿 粒子模拟/蒙特卡洛碰撞 阴极曲率半径 场致发射 数值仿真 

分 类 号：TM855[电气工程—高电压与绝缘技术]