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基于pic-mcc法的真空灭弧室电弧放电机理(英文)

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高电压技术 2011年第11期37卷 2752-2757页

作者：曹云东李静刘晓明侯春光王尔智 School of Electrical Engineering Shenyang University of Technology

With the raise of voltage level in electric power grid,the phenomena of high voltage gas insulation has received extensive attention from all over the world.The research on the breakdown mechanism of vacuum which is the main insulation gas in high voltage level is one of the most important issues.It is also important to the study of vacuum arc in vacuum switch.But for the limitations of available method used in analyzing the breakdown mechanism of vacuum,the main research on vacuum breakdown is macroscopic experiment.The experiments are greatly influenced by environmental factors and high vacuum degree is difficult to be ensured.So the data from the experiments are dispersive and the complex physical change in vacuum breakdown can not be revealed.The purpose of this work is to analyze the mechanism of vacuum breakdown quantitatively by microscopic numerical simulation.The particle in cell and Monte Carlo methods are used here to solve microscopic dynamic equation of gas.Based on the field emission theory in vacuum,electrons produced by the cathode and ions produced by the collision between electron and metal vapor molecule are the objects of this study.The motions of microscopic particles which are at the functions of the applied and self-consistent electric filed are traced in time and two space dimensions.Mont Carlo method is used here to cope with the collisions between electrons and metal vapor molecules.The cross sections of the collision which is related with the energy are all from the experiments.The secondary electron emission,exciting,elastic and ionizing collisions between electrons and metal vapor molecules have been considered in this paper.By the simulation,the number densities of electron and ion are acquired and the microscopic dynamic electric field produced by space charge is also calculated. The effect of vacuum degree on discharge voltage is also discussed here.According to the simulation data,we draw the conclusion that the main reason for vacuum arc formation is metal vapor ionization and la

关键词： pic-mcc vacuum breakdown mechanism two dimension space charge dynamic electric field Boltzmann equation

基于pic-mcc模型的真空开关弧后鞘层仿真研究

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真空科学与技术学报 2019年第11期39卷 1033-1038页

作者：李旭彬冷爽黄智慧刘芮彤邹积岩廖敏夫大连理工大学电气工程学院大连116023 国网辽宁省电力有限公司电力科学研究院沈阳110006

真空开关的零区鞘层仿真研究对于深入了解其弧后介质恢复过程具有重要意义。本文采用pic-mcc模型,研究小电流开断情况下的真空开关弧后鞘层发展过程。通过仿真得到了鞘层发展阶段的粒子空间分布、密度分布和电势分布等微观参数。采用对... 详细信息

真空开关的零区鞘层仿真研究对于深入了解其弧后介质恢复过程具有重要意义。本文采用pic-mcc模型,研究小电流开断情况下的真空开关弧后鞘层发展过程。通过仿真得到了鞘层发展阶段的粒子空间分布、密度分布和电势分布等微观参数。采用对照分析法,研究不同初始等离子体密度、原子密度和暂态恢复电压(TRV)上升率等对鞘层发展的影响,结果表明:在其他参数设置保持不变的情况下,初始等离子体密度越大,鞘层发展越慢;初始原子数密度越大,鞘层发展越慢;TRV斜率越大,鞘层发展越快。

关键词：真空开关鞘层 pic-mcc 介质恢复过程

基于pic-mcc纳秒脉冲电压下SF6/N2气体放电现象研究

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基于PIC-MCC纳秒脉冲电压下SF6/N2气体放电现象研究

作者：陈汉超哈尔滨理工大学

学位级别：硕士

SF6具有高介电强度和良好的灭弧特性,已广泛应用于电气设备的绝缘和灭弧装置中。然而SF6是一种危害大气的温室气体,近些年大部分采用SF6/N2混合气体来替代SF6。由于VFTO的出现,气体在纳秒脉冲作用下的放电过程倍受关注。因此有必要对短... 详细信息

SF6具有高介电强度和良好的灭弧特性,已广泛应用于电气设备的绝缘和灭弧装置中。然而SF6是一种危害大气的温室气体,近些年大部分采用SF6/N2混合气体来替代SF6。由于VFTO的出现,气体在纳秒脉冲作用下的放电过程倍受关注。因此有必要对短间隙纳秒脉冲下气体放电特性进行研究。本文运用一维pic-mcc（粒子网格与蒙特卡洛法结合）方法对平板电极下SF6与50%-50%SF6/N2混合气体进行数值模拟,用有限差分方法求解泊松方程,通过pic方法描述带电粒子和电场间的作用,mcc方法描述带电粒子与气体分子间的碰撞,从而将两种方法结合考察带电粒子在电场中的放电特性。分析纳秒脉冲下SF6和50%-50%SF6/N2气体放电过程,结果表明:短间隙纳秒脉冲下气体放电过程分为以下阶段:电子崩的形成发展、电子崩的汇合、电子崩链的形成发展和导电通道的产生,1mm间隙只有电子崩发展过程。模拟纳秒脉冲下1-10mm间距时SF6气体放电过程,得出极板间距由2mm增至10mm时,电子崩汇合时间由9ns缩短至6.2ns,电子崩汇合和电子崩链形成时间提前;1mm时无电子崩汇合和电子崩链产生。模拟不同纳秒脉冲电压幅值下50%-50%SF6/N2气体放电过程,脉冲电压幅值为43kV未达到放电起始电压时无电子崩汇合,电压逐渐增至50kV,电子崩汇合时间由7ns缩短至4ns,随电压增大电子崩汇合和电子崩链形成时间在提前;分析纳秒脉冲上升沿时间对50%-50%SF6/N2放电影响时,上升沿时间由6ns增至20ns,电子崩汇合时间由5.3ns增至11.1ns,随着上升沿时间增加,电子崩汇合和电子崩链形成时间在滞后;上升沿时间为2ns时,无电子崩汇合和电子崩链产生。本文通过分析纳秒脉冲电压下SF6和50%-50%SF6/N2气体放电特性,清晰地认识了纳秒脉冲电压下气体放电的发展规律,有利于气体绝缘介质在电气设备中的应用。

关键词：气体放电纳秒脉冲 pic-mcc 电子崩链绝缘

基于pic-mcc模型的真空电弧零区等离子体仿真

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基于PIC-MCC模型的真空电弧零区等离子体仿真

作者：冷爽大连理工大学

学位级别：硕士

真空断路器的研发及其开断性能的提升是当前环保型高压开断技术的重要发展方向,已成为电气学科领域的研究热点。真空断路器开断短路电流的实际物理过程十分复杂,仅靠实验手段无法详细描述其微观动态变化过程,需要将数值模拟与实验测量... 详细信息

真空断路器的研发及其开断性能的提升是当前环保型高压开断技术的重要发展方向,已成为电气学科领域的研究热点。真空断路器开断短路电流的实际物理过程十分复杂,仅靠实验手段无法详细描述其微观动态变化过程,需要将数值模拟与实验测量相结合以深入研究其开断机理。真空电弧零区过程是决定开断成功的关键阶段。真空电弧零区等离子体的数值仿真研究,能够从微观角度加深对零区复杂物理过程的理解,为提升真空断路器的开断能力、完善真空电弧理论提供重要的理论参考。本文基于粒子模拟方法（Particle-In-Cell,pic）,建立二维模型对真空电弧零区等离子体的扩散阶段进行了仿真研究。模型采用蒙特卡洛碰撞方法（Monte Carlo Collisions,mcc）处理粒子间的关键碰撞过程。本文首先在给定的初始条件下仿真分析了零区等离子体的扩散过程。然后在二维模型下,分析了初始参数的变化对零区等离子体扩散过程的影响。仿真结果表明:暂态恢复电压（Transient Recovery Voltage,TRV）变化率越高、金属蒸气密度越低,等离子体扩散越快;适当减小仿真区间对仿真结果影响较小,并且可以节省计算时间。其次,本文模拟了横向磁场分量（Transverse Magnetic Field,TMF）对零区等离子体衰减时间、粒子分布等参数的影响,并从微观角度解释了横向磁场对零区等离子体作用的物理机制。同时分析了不同初始条件下横向磁场对等离子体扩散时间、空间电势分布等参数的影响。仿真结果表明:横向磁场对等离子体扩散时间的影响主要体现在感应电场的加速与碰撞次数增加造成的阻碍作用之间的竞争关系;在低密度条件下,一定强度范围内的横向磁场分量能够促进等离子体扩散;当密度较高时,横向磁场分量阻碍等离子体扩散,对弧后介质恢复过程不利。最后,本文对比了不同微观碰撞过程对等离子体扩散时间的影响并分析了离子轰击电极表面造成的二次电子发射对等离子体扩散过程的影响。仿真结果显示:密度较低时,离子类型的碰撞过程对等离子体扩散时间影响较大;密度较高时,电子类型的碰撞过程在等离子体扩散过程中占据更大的作用;考虑电离碰撞过程时,必须考虑相应的激发碰撞,否则会使电子能量积累导致击穿,使仿真模型失效,造成较大的计算偏差;在本文给定的仿真条件下,离子轰击电极产生的二次电子发射对零区等离子体扩散有一定的阻碍作用,但总体影响较小。

关键词：真空电弧 pic-mcc 介质恢复粒子模拟

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面向深空探测的30cm离子推力器寿命预估

中国空间科学技术 2022年第6期42卷 107-114页

作者：耿海李兴达贾连军贾艳辉吴辰宸孙明明孙新锋兰州空间技术物理研究所真空技术与物理重点实验室兰州730000

为评价30 cm离子推力器的寿命,提出了有限寿命考核结合栅极仿真模型的推力器寿命预估方法,利用粒子-蒙特卡洛(pic-mcc)方法建立了栅孔溅射腐蚀模型,开展了30 cm离子推力器寿命预估研究,分析了栅孔刻蚀速率、单孔电场及离子引出特性,给出... 详细信息

为评价30 cm离子推力器的寿命,提出了有限寿命考核结合栅极仿真模型的推力器寿命预估方法,利用粒子-蒙特卡洛(pic-mcc)方法建立了栅孔溅射腐蚀模型,开展了30 cm离子推力器寿命预估研究,分析了栅孔刻蚀速率、单孔电场及离子引出特性,给出了30 cm推力器寿命预估值。结果表明,栅孔直径仿真与实测值一致性较好,误差在20%以内,基于每个寿命小节栅孔实测值对模型的修正是有效的;根据仿真结果,10000 h寿命考核后,减速栅最先失效,30 cm离子推力器在最大功率(3 kW)工况下预估寿命为37540 h,能够满足小天体探测任务对电推进系统的长寿命需求。

关键词：深空探测离子推力器寿命 pic-mcc 栅极

Discharge Simulation and Fabrication Process of an Aluminum Electrode and an Alumina Layer in AC-PDP

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Plasma Science and Technology 2013年第4期15卷 368-375页

作者：刘启发丁桂甫严群刘畅王艳 National Key Laboratory of Science and Technology on Nano/Micro Fabrication Technology Research Institute of Micro/Nano Science and Technology Shanghai Jiao Tong University Sichuan Changhong Electric Co. Ltd.

A larger space PDP cell with patterned aluminum as the addressing electrode and alumina as the dielectric layer was proposed. The aluminum electrode and the alumina dielectric layer formed on the aluminum electrode were prepared separately by magnetron sputtering and anodic oxidation for plasma display panel. The properties of the aluminum electrode and the alumina dielectric layer were tested and can meet the demand of PDP application. The resistivity of the aluminum electrode is about 5×10^-8 Ω.m, the voltage withstanding of the alumina dielectric layer exceeds 100 V/μm and the relative permittivity is about 3.5 at 1 MHz. With this structure, the manufacturing cost of PDP could be cut and the addressing discharge formative delay is reduced by 0.67%, which is proved by pic-mcc simulation.

关键词： PDP addressing discharge formative delay manufacturing cost pic-mcc

Investigation of variable aperture on the performance and lifetime of ion thruster

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Plasma Science and Technology 2021年第10期23卷 11-21页

作者：陈娟娟贾艳辉耿海郭宁郭德洲 National Key Laboratory of Vacuum and Cryogenic Technology on Physics Lanzhou Institute of PhysicsLanzhou 730030People’s Republic of China

Beam flatness is an important parameter that determines the performance and the lifetime of a gridded ion thruster.To improve the beam flatness of the 30 cm(LIPS-300)ion thruster,variable aperture ion optics that adapts to the decreasing ion density as the radius increases is proposed.It is the ion optics that the screen grid surface is divided into several zones,where the aperture diameter in each zone is determined by the ion density and the electron temperature upstream of the screen grid.The beam current density in the central area is artificially reduced.A particle in cell-Monte Carlo collision model is applied in this work to investigating the effect of variable aperture on the perveance and the maximum beam current per aperture by simulating the extraction,focusing and acceleration processes of ions.Taking into account the engineering implementability,the screen grid surface is divided into four zones.The hole diameter in each zone is decreased from 1.95 mm to 1.8 mm,1.9 mm,1.8 mm and 1.7 mm,respectively.The simulation results show that the maximum ion density in the center area of grid is decreased by10.6%and 6.99%,while it is increased by 6.49%and 22.3%in the edge region,respectively.The beam flatness of the variable aperture ion optics is improved from 0.69 to 0.88.The erosion rate is decreased by 31.9%,but the total beam current is also decreased by 7.15%.The simulation results can provide a valuable reference of the development of the ion thruster.

关键词： ion thruster variable aperture pic-mcc simulation

Three-dimensional particle-in-cell with Monte Carlo collision simulation of the electron energy distribution function in the multi-cusp ion source for proton therapy

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Chinese Physics C 2012年第10期36卷 1013-1018页

作者：杨超吴小兵刘大刚 University of Electronic Science and Technology of China Institute of High Energy Physics Chinese Academy of Sciences

For optimization and accurate prediction of the amount of proton production in the multi-cusp ion source, analysis of the electron energy distribution function （EEDF） is necessary. A three dimensional particlein-cell with Monte Carlo collision （pic-mcc） code based on the CHIpic software platform are developed. The code is applied to the multi-cusp proton source. The results show that there are two energy distributions in the discharge chamber, and a spatial non-uniformity of electron density due to the B×▽B drift of the top permanent magnets is observed.

关键词： multi-cusp proton source EEDF pic-mcc

Influence of the axial magnetic field on sheath development after current zero in a vacuum circuit breaker

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Plasma Science and Technology 2017年第6期19卷 20-25页

作者：陈毅杨飞孙昊吴翊纽春萍荣命哲 State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong University Xi'an 710049 People's Republic of China

After current zero,which is the moment when the vacuum circuit breaker interrupts a vacuum arc,sheath development is the first process in the dielectric recovery process.An axial magnetic field（AMF） is widely used in the vacuum circuit breaker when the high-current vacuum arc is interrupted.Therefore,it is very important to study the influence of different AMF amplitudes on the sheath development.The objective of this paper is to study the influence of different AMF amplitudes on the sheath development from a micro perspective.Thus,the particle in cell-Monte Carlo collisions（pic-mcc） method was adopted to develop the sheath development model.We compared the simulation results with the experimental results and then validated the simulation.We also obtained the speed of the sheath development and the energy density of the ions under different AMF amplitudes.The results showed mat the larger the AMF amplitudes are,the faster the sheath develops and the lower the ion energy density is,meaning the breakdown is correspondingly more difficult.

关键词： vacuum arc sheath pic-mcc axial magnetic field vacuum circuit breakers