The Three Dimensional Numerical Simulation Of Temperature And Fluid Flow Fields Of Plasma Arc Welding

Plasma arc welding(PAW), a high power density welding method, can fulfill one-side welding of thick plates without grooving for the high temperature, concentrated energy and complete penetration of plasma arc. Meanwhile, high depth-width ratio and better quality is gained. Therefore, PAW has a significant application in the field of aviation, space flight, and shipbuilding etc., and the simulation of plasma arc welding process is a significant research subject in welding research field.Based on theories of hydromechanics, hydrokinetics and heat transfer, a three dimensional transient numerical model of flow and temperature field of the plasma arc welding molten pool with a moving arc is established. In the model, both convection heat transfer of the melted metal inside the pool and heat conduction of solid metal outside the pool, the variation of thermophysical parameters of material with temperature, the effect of the loss of heat, including convection and radiation, and latent heat of phase transformation on the temperature field are considered. Welding heat source is presumed to be 3-D conical heat source. In use of ANSYS, calculating software of finite element technology, the welding pool's three dimensional flow and temperature fields and their transient variation processes are calculated, the flow style and velocity of molten metal are researched, and the welding variables'infection of temperature field is also analyzed.Corresponding welding experiments are done subsequently. By comparison, it's found that the calculated results approximately agree with the experimental results, which proves that the model is basically correct and the numerical method is reliable.