窄间隙摆动电弧数值模拟

Numerical Simulation of Welding Arc with Narrow Gap

为了探究窄间隙摆动电弧焊接过程中窄间隙坡口对电弧形态的影响,课题组以实际焊接工艺为依据,利用磁流体动力学理论建立了窄间隙焊接电弧燃烧侧壁的三维对称数学模型。通过对FLUENT自定义函数(UDF)二次开发,实现了对窄间隙焊接电弧的数值计算,且计算的电弧形态与试验结果吻合良好;获得了窄间隙焊接电弧的流场及温度场分布规律。计算结果表明:远离侧壁处电弧的磁感应强度大于靠近侧壁处电弧的磁感应强度;引起了等离子流场、压力场及温度场向侧壁偏转;由于窄间隙焊缝形貌影响,电弧底部等离子体沿熔池切线向焊缝凹面底部运动,并影响熔池上方电流密度及温度场的分布。

In order to investigate the influence of the narrow gap groove on the arc shape in the narrow gap swing arc welding process, magnetohydrodynamics theory was used to establish the three-dimensional symmetric mathematical model of the welding sidewall of the narrow gap welding arc based on the actual welding process. The numerical calculation of narrow gap welding arc was realized through the secondary development of the FLUENT user-defined-function(UDF), and the calculated arc shape was in good agreement with the experimental results. The distribution the flow field and temperature field of the narrow-gap welding arc were obtained. The results show that the magnetic induction intensity of the arc far away from the sidewall is greater than that near the sidewall. The plasma flow field, pressure field and temperature field are deflected toward the sidewall. The plasma at the bottom of the arc moves along the tangent of the molten pool to the bottom of the concave surface of the weld due to the influence of the narrow gap weld morphology, which affects the distribution of the current density and temperature field above the molten pool.