关键词: 微束等离子电弧, 磁流体动力学, 熔焊, 电弧轮廓

Abstract: A model of micro-plasma arc is established based on the Magnetohydrodynamics equations, which are solved with the finite element analysis software COMSOL. The results show that the temperature distribution of the arc center is in a “brush” shape from the tungsten needle to the workpiece as a whole, where the arc temperature distribution under the nozzle is in a “bell” shape, and the temperature on the workpiece conforms to the Gaussian distribution; the arc plasma has a large velocity inside the nozzle. After leaving the nozzle, its direction gradually changes from vertical downward in the nozzle to the surrounding direction when reaching the workpiece; the current flows out from the surface of the workpiece and flows into the lower end face of the tungsten electrode through the arc column, and the maximum value is obtained near the lower end face of the tungsten electrode; the flux density distribution of the arc is in a “lobes” shape. Finally, the fusion welding test was carried out, and the arc profile captured during the test was basically the same as the simulated arc shape.

Key words: Micro-plasma arc, Magnetohydrodynamics, Fusion welding, Arc profile