| Arc and droplet will affect the protective effect of the gas in the welding process,the protective effect is crucial to the welding quality, the research on the protective effect of the rotating arc sensor welding has not been reported. Rotating arc is more complex than traditional arc because of its characteristics of rotation. Conventional experimental methods on the research of the mechanism arc has certain limitations. In this paper, three-dimensional mathematical model of GMAW arc? rotating arc and compression rotating arc were presented on the basis of MHD, VOF and finite element theory, put forward the basic assumption of arc model, thermodynamic and transport properties parameters of argon and air, reasonable boundary conditions were determined,using the finite element software ANSYS CFX to numerical simulation analysis of the physics properties of arc plasma.Firstly, the gas flow field was studied by MHD and VOF method in GMAW welding process, and the effect of arc and droplet on the flow field was emphatically studied, and the flow field distribution was obtained. Research results show that the arc generated high temperature and high electric magnetic force caused gas strong turbulence diffusion effect,lead to the gas velocity is greatly improved and strong gathered to the center of arc, the protection range of the argon gas is obviously reduced compare to ignore the influence of the arc. Droplet lead to temperature decreased and arc shape changed compare to ignore the influence of the droplet,Temperature lowering directly lead to the turbulence diffusion effect of the gas will weaken, the protective effect was improved obviously.Secondly, the gas flow field is studied in the rotating arc welding process, Research results show that rotating arc shape and the temperature distribution is similar to the same condition of GMAW when consideration of the arc and ignore the droplet impact, but argon gas distribution regularity is different On work piece surface,GMAW argon gas distribution is symmetrical but the left protection effect is far better than right of rotating arc due to the eccentricity of the conductive rod and wire rotation. The rotating arc temperature is lower than that of GMAW when considering the influence of molten drop, this is due to the welding wire rotating lead to a centrifugal force woke on droplet, the molten drops falling speed, heat taken away more quickly.Finally, the gas flow field is studied in the,compression rotating arc welding process, Research results show that arc shape and ordinary rotating arc almost no difference when considering the effect of arc, but the temperature is higher than ordinary rotating arc, and the protective effect is slightly worse than that of ordinary arc protective effect,this is due to the increase of temperature, gas turbulence diffusion effect is stronger.Results of this study that is providing a theoretical reference for the selection of rotating arc welding process parameters, the nozzle structure design and the study of molten pool. |
PDF Full Text Request