Abstract: A mathematical model for plasma arc generator is established based on the mass, momentum and energy conservation equations and the Maxwell equations. The model includes a part of tungsten electrode to avoid the assumption of current density distribution near the cathode. The flow state of the plasma arc is also considered. The model is solved with the ANSYS finite element analysis software. The temperature and velocity distributions of the plasma arcs produced by different plasma arc generators are analyzed. The effects of nozzle size, electrode tip shape and arc type on the plasma arc characters are studied. The results show that nozzle with a bigger aperture ratio may produce a higher temperature and higher velocity plasma arc. The aperture ratio even may change the flow state of the plasma arc. The plasma arc with a rounded-tip cathode got the highest temperature near the exit of the nozzle, while the one with a subulate-tip cathode got the highest temperature at the front of the cathode. The transferred plasma arc has a higher temperature and velocity than non-transferred plasma arc. The work has testified that mathematical simulation is meaningful for the development of plasma arc generator.

Key words: ANSYS, Mathematical simulation, Plasma arc generator, Temperature, Velocity