外部磁场对直流电弧等离子体放电特性的影响及其机理  

Influence and Its Mechanism of External Magnetic Field on DC Arc Plasma Jet

作　　者：胡明[1] 万树德[1] 夏洋洋[1] 任真诚[1] 邱志坚 

机构地区：[1]中国科学技术大学近代物理系,合肥230026 [2]江苏省晶瑞石英工业开发研究院有限公司,连云港222004

出　　处：《高电压技术》2013年第7期1655-1660,共6页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2008CB717800)~~

摘　　要：通过外部磁场驱动电弧旋转产生相对均匀的等离子体是一种可能的改进等离子体放电特性的有效手段。利用高速摄像技术和虚拟仪器技术,观察并测量了大气条件下、非均匀磁场驱动的直流电弧等离子体阳极弧根运动以及电弧电压波动。结果发现:相比无外部磁场,非均匀外部磁场驱动下的直流电弧等离子体在旋转力和稳弧力的作用下阳极弧根旋转,均匀性提高;其电弧电压波动幅度增大,放电模式发生改变;伏安特性曲线向上平移,电弧等离子体炬放电功率提高。另外,由于等离子体射流的高速运动而引起的等离子体射流在喷口处径向扩张,使等离子体射流横截面扩大,进一步提高了射流的均匀性。从结果中可以看出,外部磁场改善了直流电弧等离子体炬的基本特性,对直流电弧等离子体炬应用效率的提高具有重要的意义。It is a promising measure to generate relatively uniform arc plasma by making the arc rotated through external magnetic field for improving the quality of plasma spraying.Using a high-speed video camera and virtual instrument technology,we measured the movement of anode arc root and the fluctuation of arc voltage of DC arc plasmas driven by non-uniform magnetic field under atmospheric pressure.The results show that,compared with the arc in the absence of external magnetic field,the arc root turns,the curve of the volt-ampere characteristic shifts up,and power of the DC arc plasma torch increases due to the rotational force and the stable arc force caused by the external magnetic field.In addition,since the plasma jet was expanded in radial direction at the nozzle due to high-speed movement,its cross section increased,and the homogeneity of plasma jet was increased.It is concluded that the external magnetic field can improve the basic characteristics of DC arc plasma torch,which is quite meaningful for further application of DC arc plasma.

关 键 词：直流电弧等离子体炬 外部磁场驱动 旋转阳极弧根 电弧电压波动 伏安特性曲线 等离子体射流 

分 类 号：O53[理学—等离子体物理]