层流等离子体发生器设计关键技术研究之双弧现象

发布时间：2018-03-14 21:37

本文选题：层流等离子体　切入点：双弧现象　出处：《工程科学与技术》2017年03期 　论文类型：期刊论文

【摘要】：分段式结构设计通常被应用于层流等离子体发生器的结构设计中,以避免产生大尺度分流现象,进而避免层流等离子体射流产生脉动。然而,在分段式层流等离子体发生器中,当中间电极长度较长时,经常在该中间电极上产生一个新的阳极弧根和阴极弧根(即双弧现象),导致该电极热负荷严重,造成电极的严重烧蚀和等离子体射流的波动。为了延长层流等离子体发生器中间电极寿命,提高层流等离子体射流稳定性,必须对双弧现象加以抑制。本文基于假设条件,首先建立了层流等离子体发生器正常工作时和产生双弧现象时的分析模型,分析了双弧现象产生机理,并基于最小电压原理,推导出层流等离子体发生器不产生双弧现象对中间电极的尺寸要求;然后,基于前述双弧现象产生原理分析和理论推导,确定了抑制层流等离子体发生器产生双弧现象的措施如下:一是,增加冷气膜击穿电压U_b,使电弧与弧室壁的电势差不足以击穿二者间的冷气膜;改善等离子体发生器冷却通道,优化其对弧室壁的冷却效果,进而降低冷气膜的温度;增大工作气体流量,增强对电弧的压缩,进而增加冷气膜的厚度。二是,限制中间电极轴向长度,降低电弧在对应中间电极区间的电压降,即任意中间电极在轴向的长度均满足最小电压要求。
[Abstract]:The segmented structure design is usually used in the structural design of laminar plasma generator to avoid the phenomenon of large scale shunt and thus to avoid the pulsation of laminar plasma jet. However, in the segmented laminar plasma generator, When the length of the intermediate electrode is longer, a new anode arc root and cathode arc root (that is, double arc phenomenon) are often produced on the intermediate electrode, which results in a serious thermal load on the electrode. In order to prolong the life of intermediate electrode of laminar flow plasma generator and improve the stability of laminar plasma jet, the phenomenon of double arc must be restrained. Firstly, the analytical model of laminar flow plasma generator during normal operation and double arc phenomenon is established, and the mechanism of double arc phenomenon is analyzed, and based on the principle of minimum voltage, It is deduced that the laminar flow plasma generator does not produce the double arc phenomenon and the size of the intermediate electrode is required, and then, based on the above two arc phenomena, the principle of the generation and the theoretical derivation are derived. The measures to restrain the double arc phenomenon of laminar flow plasma generator are determined as follows: first, increasing the breakdown voltage Ubso that the potential difference between the arc and the wall of the arc chamber is not enough to break through the cold film between the two, and improving the cooling channel of the plasma generator, The cooling effect on the wall of the arc-chamber is optimized to reduce the temperature of the air-cooled film, to increase the working gas flow rate, to increase the compression of the arc, and to increase the thickness of the air-cooled film. Second, to limit the axial length of the intermediate electrode, Reducing the voltage drop of the arc in the corresponding intermediate electrode region, that is, the axial length of any intermediate electrode meets the minimum voltage requirement.
【作者单位】：四川大学制造科学与工程学院;
【基金】：四川省科技厅高新技术发展与产业化重点研究项目(2017GZ0096) 四川大学引进人才基金资助项目(yj2012043)
【分类号】：O539

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