外加变位磁场作用GTAW焊接电弧的数值模拟

Numerical Simulation of GTAW Welding Arc under the External Static Magnetic Field of Changing Position

为了揭示外加变位磁场对GTAW焊接电弧的形态以及传热传质影响规律,建立了GTAW焊接电弧的数学模型;对比分析了无外加磁场,30°变位磁场,60°变位磁场作用下XZ截面(即Y=0截面)的电弧温度场、压强以及Z=7.5 mm截面电磁力矢量的变化规律;并在电弧空间取一条路径Path1(X方向),详细对比分析了此路径上的电流密度、电弧温度、X方向电磁力分量、Y方向电磁力分量、压强、X方向速度分量、Y方向速度分量的分布规律.结果显示:外加变位磁场作用下的XZ截面的电弧温度场、压强以及Z=7.5 mm截面电磁力矢量均不再呈现对称分布.在Path1上随着变位角度的增加,电弧X方向电磁力分量“波峰”上移、“波谷”下移;电弧Y方向电磁力分量由零变为“双峰分布”,再变为“单峰分布”,且“波峰”上移;电弧X方向速度分量由类似余弦函数分布逐渐变为“单峰”分布,且“波谷”下移;电弧Y方向速度分量由零逐渐变为类似正弦函数分布,且“波峰”下移,“波谷”上移.

In order to reveal the effect of external magnetic field of changing position on the shape,heat and mass transfer of GTAW welding arc,a mathematical model of GTAW welding arc was established,and changeable rule of arc temperature field,pressure of cross section XZ(i.e.y=0 section)and electromagnetic force vector of Z=7.5 mm section under the action of no external magnetic field,30 degree displacement magnetic field and 60 degree displacement magnetic field are compared and analyzed.Path1(X direction)are selected in the arc model,and the distribution laws of current density,arc temperature,electromagnetic force,pressure,velocity and potential on this path are compared and analyzed in detail.The results show that the arc temperature field,pressure in XZ section(i.e.y=0 section)and electromagnetic force in Z=7.5 mm section no longer show symmetrical distribution under the action of external magnetic field.With the increase of the displacement angle on Path1,the"peak"of the electromagnetic force component in the X direction of the arc moves up and the"valley"moves down;the electromagnetic force component in the Y direction of the arc changes from 0 to"bimodal distribution",and then to"unimodal distribution"with"peak"moving upward;the velocity component of the arc X direction gradually changes from a"similar cosine function"distribution to a"single peak"distribution,and the"valley"moves downward;the arc Y direction velocity component gradually changes from 0 to a similar sine function distribution with"peak"moving down,the"valley"moving up.