Numerical investigations of arc behaviour in gas metal arc welding using ANSYS CFX
Numerical investigations of arc behaviour in gas metal arc welding using ANSYS CFX
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DOI：
10.1007/s11706-011-0134-4
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发表时间：
2011-05
影响因子：
2.7
通讯作者：
M. Schnick;U. Fuessel;M. Hertel;A. Spille-Kohoff;A. Murphy
中科院分区：
文献类型：
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作者：
M. Schnick;U. Fuessel;M. Hertel;A. Spille-Kohoff;A. Murphy
目前的气体保护金属极电弧焊（GMAW）数值模型试图将电弧的联合收割机磁流体动力学（MHD）模型和金属过渡的流体体积（VoF）模型结合起来。他们忽略了汽化，并假设电弧区域为氩气气氛，因为这是气体保护钨极电弧焊模型的常见做法。这些模型预测的温度高于20 000 K，温度分布类似于钨极惰性气体（TIG）电弧。然而，在GMAW电弧中的当前光谱温度测量显示出低得多的电弧温度。与TIG电弧相反，他们发现了径向温度分布的中心局部最小值。本文提出了一种考虑金属蒸气的GMAW电弧模型，该模型与实验观察到的温度非常吻合。此外，该模型能够预测局部中心极小值的径向温度和径向电流密度分布的第一次。焊炬、工件、焊丝和电弧（流体域）的轴对称模型实现了MHD以及氩气中金属蒸气的湍流混合和热分层。从模拟中得到的铁蒸气的质量分数显示在2000至5000 K时在电弧核心中的积聚和在电弧边缘上的另一积聚。分层效应导致这两个区域之间的铁浓度非常低。敏感性分析表明，金属蒸气的传输和辐射特性的影响，以及相对于送丝的蒸发速率。最后将模型预测结果与Zielienska等人的测量结果进行了比较。
Current numerical models of gas metal arc welding (GMAW) are trying to combine magnetohydrodynamics (MHD) models of the arc and volume of fluid (VoF) models of metal transfer. They neglect vaporization and assume an argon atmosphere for the arc region, as it is common practice for models of gas tungsten arc welding. These models predict temperatures above 20 000 K and a temperature distribution similar to tungsten inert gas (TIG) arcs. However, current spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to TIG arcs they found a central local minimum of the radial temperature distribution. The paper presents a GMAW arc model that considers metal vapour and which is in a very good agreement with experimentally observed temperatures. Furthermore, the model is able to predict the local central minimum in the radial temperature and the radial electric current density distributions for the first time. The axially symmetric model of the welding torch, the work piece, the wire and the arc (fluid domain) implements MHD as well as turbulent mixing and thermal demixing of metal vapour in argon. The mass fraction of iron vapour obtained from the simulation shows an accumulation in the arc core and another accumulation on the fringes of the arc at 2000 to 5000 K. The demixing effects lead to very low concentrations of iron between these two regions. Sensitive analyses demonstrate the influence of the transport and radiation properties of metal vapour, and the evaporation rate relative to the wire feed. Finally the model predictions are compared with the measuring results of Zielińska et al.