Numerical analysis on plasma gas fluid field of N_2-Ar protecting TIG welding arc

N2-Ar protecting tungsten inert gas(TIG)welding arc is chosen as the studied object. A mathematic model is developed according to the theory of magnetic fluid dynamics. TIG welding arc is numerically analyzed based on this 2D, static and axisymmetric model with ANSYS software and the temperature and velocity profiles of the φ(N2)50%+Ar protecting arc have been simulated. The analysis indicates that the max-temperature of the arc appears near the anode and the max-current density, the max-velocity of the plasma and the max-arc pressure appear near the cathode. The influences of different current and arc length on the distribution of current density on anode are analyzed. The current density increases with the increasing of current and diminishes with the increasing of arc length.