全局磁场作用下多组份真空电弧三维特性研究

Vacuum arc characteristics and its magnetic field control is critical for the interruption characteristics of vacuum interrupters. In the actual axial magnetic field (AMF) electrode, vacuum arc is controlled by global magnetic fields (GMF), which includes AMF and radial magnetic field generated by electrode system, azimuthal magnetic field generated by vacuum arc, and also transverse magnetic field generated by external bus-bar, not only AMF. The interaction among GMF and multi-component arc column plasma, electrode process, liquid droplet is very significant. In this project, self-consistent model with consideration of bidirectional coupling between GMF and vacuum arc behavior will be established, and related experimental verification will be conducted. Based on the simulation and related experiments, the evolution law of vacuum arc and liquid droplets subjected to GMF will be researched. At first, GMF calculation model of electrode system with consideration of arc deformation is established. Then, self-consistent model with consideration of bidirectional coupling between GMF and three dimensional vacuum arc characteristics will be established, and its numerical solution method will be studied. The above vacuum arc should include the interaction between electrode process (cathode spots distribution and anode vapor), liquid droplet and arc column plasma. Then, based on the above model, 3d vacuum arc under different GMF conditions will be simulated, and the evolution law of vacuum arc temperature, liquid droplet velocity, density of plasma species, electrode erosion, arc voltage, and other parameters will be researched. At the same time, the special experiments will be designed to research micro-parameters of vacuum arc subjected to GMF, and experimental results will be used to verify the simulation results. Based on the research of this project, the evolution law and its physical mechanism of vacuum arc characteristics subjected to GMF will be disclosed, and it also can supply theoretical support for the development of vacuum interrupters towards large-capacity, miniaturization, and higher-voltage class.

真空电弧特性及其磁场控制对真空开关的开断性能十分关键。在实际的纵磁电极中，真空电弧处于电极系统产生纵向、径向、电弧自生旋向磁场及外部母线产生横向磁场并存的全局磁场作用之下，而并非单纯的纵向磁场。全局磁场与多组份弧柱、液滴、电极过程之间的相互作用明显。本项目通过建模仿真及实验验证的方法，研究全局磁场下多组份真空电弧和液滴特性的演变规律。先建立电弧形变及外电路条件下电极系统的全局磁场模型；再建立全局磁场与多组份真空电弧三维特性(含电极过程、液滴与弧柱的相互作用)双向耦合的自洽模型，研究其数值求解方法；并对不同全局磁场下的真空电弧进行仿真，研究电弧温度、液滴速度、等离子体组份密度、电极烧蚀、电弧电压等参数的变化规律；同时，设计实验，研究全局磁场下的真空电弧微观特性，并对仿真进行验证。通过研究，掌握全局磁场下真空电弧特性的演变规律与物理机制，为真空开关向大容量、小型化及高电压等级发展提供理论借鉴。

真空电弧特性及其磁场控制对真空开关的开断性能十分关键。在实际的纵磁电极中，真空电弧处于电极系统产生纵向、径向、电弧自生旋向磁场及外部母线产生横向磁场并存的全局磁场作用之下，而并非单纯的纵向磁场。全局磁场与多组份弧柱、液滴、电极过程之间的相互作用明显。本项目首先建立了全局磁场下真空电弧的三维多组分磁流体动力学模型，计算了不同纵磁触头的空间磁场分布，然后仿真分析了电弧的特性参数和组分分布，仿真结果表明杯状纵磁触头产生的磁场更均匀，对于线圈式触头，线圈匝数越大，纵磁对电弧收缩的抑制越明显；其次，建立了考虑阳极蒸汽的多组分真空电弧模型，当阳极温度较高时，阳极蒸汽将进入电弧中，形成一个低温低电导的区域，该区域的大小取决于阴极侧等离子体压力和阳极射流压力的平衡，该仿真结果与实验结果吻合较好；进一步建立了考虑阳极模式和触头打开过程的多组分真空电弧三维仿真模型，对全局磁场下的电弧组分分布以及其他等离子体参数特性进行了仿真研究，仿真结果表明，由于阳极蒸气以及纵向磁场的存在，等离子体温度更低，尤其是中性原子蒸汽区内，同时，在大尺寸电极条件下，阳极蒸汽很难进入弧柱；采用全局磁场仿真与大电流真空电弧实验相结合的方法研究了触头系统全局磁场分布对电弧特性的调控作用及对阳极特性的影响。本项目建立了阴极斑点烧蚀以及液滴形成的三维热力学模型，并开展了相关仿真研究。基于粒子模拟的方法，仿真分析了横向磁场和纵向磁场作用下弧后等离子体的扩散过程。在本项目资助下共培养6名博士生、9名硕士生，在Applied Physics Letters 等权威期刊发表论文44篇(其中特色论文、封面论文2篇，综述论文2篇)、国际会议论文8篇(大会特邀报告1次)，获国家发明专利3项，软件著作权3项。获英国物理学会（IOP）出版集团2019年度和2020年度中国高被引作者奖（前1%）。博士生杨泽第29届真空放电与电气绝缘的国际会议(2021年)唯一CHATTERTON杰出青年奖，4名硕士生获西安交通大学优秀硕士论文。通过该项目研究，掌握了全局磁场下真空电弧特性的演变规律与物理机制，为真空开关向大容量、小型化及高电压等级发展提供了理论借鉴。