磁扩散电弧运动图像实验研究

Experimental study on arc movement images effected by magnetic diffusing

电弧等离子体与气体之间的相互作用机理研究一直在低温等离子领域受到关注。为了获得比较均匀的大面积直流电弧等离子流,设计了一种利用外磁场驱动电弧旋转的等离子发生器。利用高速摄影技术研究了大气压条件下氩电弧等离子体在弧室中的运动情况,得到了典型的螺旋型电弧照片,分析了外部磁场对电弧运动形状、电弧电压的影响和弧根附近的气流扰动情况,认为磁场分布的不均匀性是导致电弧形状多样性和不稳定性的主要原因,而阴极烧蚀引起了弧根区气流扰动的不对称性。

The investigation of mechanisms of the reciprocity between arc plasmas and gas is one of the most attractive characteristics in the low-temperature plasma field. In order to obtain a more uniformity flow of the de arc plasma, the large-scale arc hollow electrode plasma generator with an outer magnetic field is designed in this paper. A photogrammetry was built to investigate effect of arc movement with the aid of a highspeed digital camera in the argon plasma under the atmospheric pressure condition. Typical arc images of spiral shape and arc voltage are measured, and some phenomena observed are interpreted and analyzed with dynamic mechanism. It points that the arc shape diversification and instability, and dissymmetrical swirl figure near the arc root are caused by no-uniformlty external magnetic field. Moreover, the no-uniformlty magnetic field can prick up the cathode ablation.