Visualization of fume formation process in arc welding with numerical simulation
Visualization of fume formation process in arc welding with numerical simulation
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DOI：
10.1016/j.surfcoat.2012.05.114
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发表时间：
2013-08
影响因子：
5.4
通讯作者：
S. Tashiro;Tasuku Zeniya;A. Murphy;Manabu Tanaka
中科院分区：
文献类型：
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作者：
S. Tashiro;Tasuku Zeniya;A. Murphy;Manabu Tanaka
为了弄清电弧焊烟尘的形成机理，必须对电极、电弧和熔池之间的相互作用进行定量研究。以布朗力和库仑力为粒子驱动力，建立了由非均相凝聚模型、均相成核模型和凝聚模型组成的烟尘生成模型，并与GMA焊接模型耦合。利用该模型对金属蒸气从蒸发到烟气生成的一系列过程进行了全面的模拟研究。本文旨在通过数值分析，从理论上对烟气形成过程进行可视化研究，阐明烟气形成机理。通过与实验结果的对比，对仿真模型的可靠性进行了评价。结果，还澄清了大部分烟雾产生于电弧的下游区域，其来源于主要从液滴蒸发的金属蒸汽。这种烟雾是由几个纳米大小的颗粒组成的。另一方面，如果金属转移变得不稳定，并且熔滴附近的金属蒸气直接向电弧周围扩散而不进入等离子体流，则颗粒的尺寸达到1μm。
In order to clarify fume formation mechanism in arc welding, quantitative investigation based on understanding of interaction among the electrode, arc and weld pool is indispensable. A fume formation model consisting of heterogeneous condensation model, homogeneous nucleation model and coagulation model considering Brownian force and Coulomb force as driving force of particle has been developed and coupled with a GMA welding model. A series of processes from evaporation of metal vapor to fume formation from the metal vapor was totally investigated by employing this simulation model. This study aims to visualize the fume formation process and clarify the fume formation mechanism theoretically through numerical analysis. Furthermore, the reliability of the simulation model was also evaluated through comparison of the simulation result with experimental result. As a result, it was also clarified that most part of the fume was produced in downstream region of the arc originating from the metal vapor evaporated mainly from the droplet. This kind of fume was constituted of particles with size of several nm. On the other hand, if the metal transfer becomes unstable and the metal vapor near the droplet diffuses directly toward the surroundings of the arc not getting on the plasma flow, the sizes of particles reach 1μm.