基于Fluent软件的Keyhole-TIG焊接电弧的数值模拟

Numerical Simulation of Keyhole-TIG Welding Arc Based on Fluent Software

以自由燃烧的Keyhole-TIG电弧为研究对象,建立了统一电弧-钨极-阳极的二维轴对称模型。采用Fluent软件对焊接电流为520 A的稳态Keyhole-TIG电弧进行了模拟,以获得电弧的温度、速度、压强和电流密度等物理量及其分布。结果表明:钨极下方电弧的最高温度达36000 K;电弧出现强烈的阴极喷射,高速等离子体产生的动压力是形成小孔的主要原因;由于小孔的泄压作用,阳极表面附近未形成明显的高压区;大部分电流从阳极工件上表面流入钨极,仅19%的电流从小孔中进入;电弧传入小孔的热量占总热量的17%,剩余热量通过阳极上表面进入。

Taking the free-burning Keyhole-TIG arc as a research object,a two-dimensional axisymmetric model unifying arc-tungsten-anode was established.The steady-state Keyhole-TIG arc with a welding current of 520 A was simulated by a Fluent software to obtain physical variables such as temperature,speed,pressure,and current density of the arc and their distribution.The results showed that(a)the maximum temperature of the arc under the tungsten electrode was up to 36000 K;(b)the arc exhibited a strong cathode jet,and the formation of keyholes was traced largely to dynamic pressure generated by the high-speed plasma;(c)no obvious high-pressure area formed near the anode surface because the keyhole acted as pressure relief;(d)most of the current flowed from the upper surface of the anode workpiece to the tungsten electrode,and as little as 19%of the current entered through the keyholes;and(e)the heat the arc transferred into the keyhole accounted for 17%of the total heat,and the remainder entered through the upper surface of anode.