双钨极耦合电弧数值模拟

Numerical simulation of coupled arc in double electrode tungsten inert gas welding

基于流体力学方程组和麦克斯韦方程组,在合理的边界条件下,建立了双钨极耦合电弧三维准静态数学模型.通过对方程组的迭代求解,获得了不同钨极间距和电弧长度下耦合电弧的温度场、流场、电弧压力和电流密度分布等重要结果,与已有的实验研究符合良好.模拟结果表明:与相同条件下的钨极惰性气体保护焊电弧相比,双钨极耦合电弧的最高温度和最大等离子流速较低,阳极表面电弧压力和电流密度峰值明显减小;钨极间距和弧长对耦合电弧的温度场、流场、电流密度和电弧压力等都具有显著的影响,且耦合电弧阳极的电弧压力和电流密度分布不能用高斯近似进行描述.

A three-dimensional quasi-steady state mathematical model for the coupled arc in double electrode tungsten inert gas （TIG） welding is established based on the fluid dynamic equations and Maxwell equations under the reasonable boundary conditions. By solving these equations, the distributions of temperature, velocity, arc pressure and current density of the coupled arc are obtained. The results accord well with previous experimental results. It is found that the maximum temperature and plasma velocity of the coupled arc decrease compared with those of the TIG arc in the similar conditions. The peak value of arc pressure and current density at the anode surface decline sharply. Both the electrode spacing and arc length have significant influences on temperature and flow field, current density, and arc pressure of the coupled arc. Furthermore, coupled arc pressure and current density at the anode cannot be described by Gaussian assumption.