Ar与H2混合气体保护下GTAW电弧特性数值模拟

针对Ar与H₂混合气体保护下GTAW焊接电弧的传热与流动特性，建立基于磁流体动力学的二维轴对称数学模型，结合麦克斯韦方程组与流体动力学理论对电弧的温度、电势、电弧压力以及电流密度等进行求解，又分别将传统氩弧与氩氢混合气体保护下电弧的阳极热进行分析与对比.结果表明，加入10%氢气后的电弧轮廓较传统氩弧略微收缩，电磁力增至约传统氩弧的2倍，温度、等离子体流速、电势、电流密度等都明显增大，导致更多热量传递给阳极，在一定程度上提高了焊接热效率.可为高效GTAW焊接工艺的进一步开发提供理论参考.

Numerical simulation of arc characteristics under mixtures of argon and hydrogen in gas tungsten arc welding

An axisymmetric model based on the magnetohydrodynamic (MHD) is established to investigate the effect of hydrogen on heat transfer and fluid flow characteristics of argon plasma in GTAW. The profiles of temperature and voltage drop, distributions of arc pressure and current density are simulated by utilizing the fluid dynamic theory coupled with Maxwell equations. The quantitative analysis and comparison of anodic heat fluxes under pure argon and mixtures of argon and hydrogen are also obtained. The results show that the addition of 10% hydrogen to argon makes the arc slightly constricted and increases electromagnetic forces up to 2 times of the conventional arc. Meanwhile, it also increases the temperature, plasma flow velocity, arc voltage, current density. This leads to more energy transferred to the anode, which can partly improve the thermal efficiency. The present study may provide theoretical reference for the further applications of high efficiency GTAW process.