GTAW焊电弧的磁流体动力学数值分析

Numerical analysis for GTAW arc with MHD model

基于磁流体动力学理论建立GTAW电弧的二维稳态轴对称模型,通过FLUENT14.5软件对不同电流和不同氩气流量下的电弧特性进行数值模拟,模拟得到不同焊接电流条件下电弧的温度场、速度场、压力场、电流密度和工件表面的总热流量。结果表明:当电流增加时,电弧区能量升高,电弧的参数均会增大;氩气流量的增加,电弧等离子体的最高温度先升高后降低。为获得更高的温度场,有一个合适的气体流量范围,电弧压力有小幅增加,但氩气流量的改变对其他参数的影响不大,可见在电弧区电磁力占主导因素。

Based on the theory of Magneto-Hydrodynamic(MHD),a steady two-dimensional axisymmetric GTAW arc model was established. The arc characteristics under different current and different argon flow rate were simulated with the software of FLUENT14.5. The temperature field,velocity field,pressure field,current density of arc and the total heat flow on the surface of the workpiece were obtained under the condition of different welding current. The results show that,when the current increases,the energy of the arc area increases and the parameters of the arc will also increase. With the increase of argon flow rate,the maximum temperature of arc plasma firstly increases and then decreases. So in order to obtain high arc temperature,there is an optimum range for gas flow rate. In addition,with the increase of argon flow rate,arc pressure has a modest increase,the change of argon gas flow rate has little effect on the other parameters. It can be concluded that the electromagnetic force in the arc area is the dominant factor.