物理学报2018，Vol.67Issue(4)：143-153,11.DOI:10.7498/aps.67.20172309
针-板空气间隙流注放电起始过程的三维PIC/MCC仿真研究
Three-dimensional PIC/MCC numerical study on the initial process of streamer discharge in a needle-plate electrode in atmospheric air
摘要
Abstract
Streamer, which usually appears at the initial stage of atmospheric pressure air discharge, acts as a precursor of lightning. It also occurs as large discharges (called sprites) in upper atmosphere, far above the thundercloud. The streamer discharge has many potential applications in industry, such as gas or water cleaning, ozone generation, assisted combustion, etc. The streamer discharge is difficult to investigate both experimentally and computationally, because of its non-linear and multi-scale characteristics. Various studies on streamer discharge have been carried out, and some progress has been made. However, some things remain to be further understood, i.e., the law of particles motion and the factors influencing streamer discharge. In this paper, we use a pre-established three-dimensional (3D) particle model (PIC/MCC) to study streamer discharge with a needle-plate electrode in air. To simplify the condition, we only use nitrogen-oxygen mixture to represent dry air, regardless of other components such as CO2, H2O gases, etc. In this model, we take photoionization, attachment and detachment processes into account. The adaptive mesh refinement and adaptive particle weight techniques are used in the code. In order to facilitate the simulation, we artificially put a Gaussian seed right on the top of the needle electrode. We adjust some computational parameters to analyze how the streamer discharge starts and evolves from the needle electrode. Many factors can influence streamer discharge during its evolution, from among which we choose three important parameters: voltage amplitude, gas component, and the radius of curvature of the needle electrode tip, to study the generation and evolution of streamer discharge, and focus on inception cloud, streamer branches, and electric fields. The simulation results show that the radius of inception cloud increases with the increase of voltage amplitude, and the diameter of steamer channel and the number of branches also increase with voltage increasing. We choose 4 kV as a proper simulation voltage for next two parts of simulations. By comparing the results obtained in the cases of different gas components (pure oxygen and different ratios of nitrogen-oxygen mixtures), we discover that the nitrogen-oxygen mixture ratio significantly affects the total number of streamer branches. With 0.1%oxygen, discharge grows irregularly with small protrusions on streamers. In the pure oxygen case, streamer seems to have much more thin branches than in other cases. Needle geometry directly changes the inception cloud of the streamer and its morphology, especially when the tip becomes blunter. In this circumstance, electric field strength around the electrode decreases, and inception cloud can be barely seen. Instead, a single-channel streamer discharge develops right toward the plate electrode, later this single-channel streamer splits into branches.关键词
流注放电/三维粒子仿真/针-板电极Key words
streamer discharge/3D particle simulation model/needle-plate electrode引用本文复制引用
李晗蔚,孙安邦,张幸,姚聪伟,常正实,张冠军..针-板空气间隙流注放电起始过程的三维PIC/MCC仿真研究[J].物理学报,2018,67(4):143-153,11.基金项目
国家自然科学基金(批准号: 51777164)、西安交通大学"青年拔尖人才支持计划"(批准号: DQ1J008)、电力设备电气绝缘国家重点实验室(批准号: EIPE17311)和中央高校基本科研业务费专项资金(批准号: 1191329723)资助的课题.Project supported by the National Natural Science Foundation of China (Grant No. 51777164), "the Young Talent Plan"of Xi'an Jiaotong University (Grant No. DQ1J008), State Key Laboratory of Electrical Insulation and Power Equipment (Grant No. EIPE17311), and the Fundamental Research Funds for the Central Universities, China (Grant No. 1191329723). （批准号: 51777164）
