中文摘要：

基于磁流体力学（magnetohydrodynamics,MHD）模型,采用动网格技术（dynamic mesh method,DMM）跟踪电弧-焰池界面,建立了钨极惰性气体（tungsten insert gas,TIG）保护焊过程親合流动、传热、凝固熔化及动网格界面跟踪的数学模型.首先计算自由燃弧,得到了准确的弧区速度、温度及压力等参数.然后分别验证了熔池内电磁力、热浮力、等离子流曳力和Marangoni力4个驱动力.考虑上述电弧-熔池相互作用,基于压力的动态平衡跟踪界面,计算了304不锈钢TIG焊过程,得到了等离子体冲击造成的熔池中央下凹及边缘上凸现象.结果表明,本模型可以得到更准确的界面及熔池形状.

英文摘要：

Based on the magnetohydrodynamic （MHD） model, the dynamic mesh method （DMM） was used to track arc-molten pool interface,and a mathematical model for coupled fluid flow,heat transfer, solidification/melting and dynamic interface tracking during TIG welding process was established. Firstly, a free-burning arc was simulated to obtain the accurate arc parameters, such as the speed, temperature and pressure. Then, the four driving forces of electromagnetic,thermal buoyancy,drag and Marangoni were validated respectively. Considering the arc-molten pool interaction and tracking the interface from pressure balance, the TIG welding process for the 304 stainless steel was simulated and the depression in the pool center and the lifting on the pool periphery caused by plasma shock were obtained. It is shown that the proposed model can simulate the arc-pool interface and molten pool shape more accurately in comparison with the experimental data.