Study On Simulation Analysis Of Plasma Welding Arc

The plasma has been used greatly in the fields of aviation and manufacturing of auto for its characteristic of high energy density, upright and outspoken and smaller heat infection area. The plasma welding arc is hard to be measured just because its temperature is too high. So right now we can not to measure it. With the development of numerical analysis, the research of plasma of welding arc becomes to be possible. We use Ansys and the theory of magnetic fluid dynamics as our tools to make up the model of plasma welding arc here.First we separate the model to different parts, such as anode, cathode and protecting gas's field. Then we mesh the model. In order to keep the precision of calculation, we made the mesh of important fields smaller. The electric field has been calculated first. Then the result is imported to the calculation of the magnetic field. The third step is to calculate the fluid field.We contrasted the calculated temperature results of plasma welding arc and the TIG The result shows that with the same welding parameters the PAW arc's temperature is higher than the TIG's. The diameter of the PAW arc is still smaller than the TIG arc. And the heat flux density of the PAW arc is greater than the TIG arc.We analysze the PAW arc with Ar-N₂ working gas. The result shows that with the mixed working gas the characteristic of the arc changed greatly. The diameter became smaller. The maximum temperature field moved to the anode. The heat flux at anode was higher than the argon arc. So with the same welding parameters we could increase the input of heat to the anode with the method of using mixed working gas. Double arc could make the welding arc unstable. We simulate the double arc aroused by the reasons of too big welding current, too small diameter of the nozzle and eccentric of the cathode. The research show that the double arc made the current density at anode smaller. This phenomenon makes the temperature of the welding arc lower. At the same time, the temperature of the nozzle increased. The temperature distributions are the same. The cathode spot made the nozzle burn.The analysis model of plasma welding arc that we set up here gives a base function to the research of moving arc and offers some useful boundary conditions to the research of the unite model of anode and welding arc.