【作者】 李彩辉；

【导师】 雷玉成；

【作者基本信息】 江苏大学 ， 材料加工工程， 2006， 硕士

【摘要】 氩氮混合气体保护的TIG焊接电弧因为同时具有氩气电弧和氮气电弧的特性，具有高的热特性，因此越来越受到关注。本文运用ANSYS软件对氩氮保护直流TIG焊电弧进行数值模拟，同时对氩氮保护TIG焊接电弧的电特性和热特性进行了实验研究。 本文根据磁流体动力学理论，应用流体动力学方程和麦克斯韦方程，建立直流氩氮气体保护TIG焊电弧轴对称数学模型，并以之模拟焊接电弧的热过程和流体流动。 模型中采用了符合实际的具有尖端的阴极形状，选取合理的边界条件，氩气和氮气物性参数对温度高度非线性，计算电场时将阴极和弧柱结合起来，避免对阴极电流密度分布的假设。在ANSYS软件分析中采用模块化计算，分别建立温度场、电磁场和流场的几何模型，相互调用计算结果迭代运算。 采用温升法测量了电弧的热功率和静特性。通过测试发现，随着氮气含量的增大，电弧电压逐渐增大。对电弧热功率的计算表明，随着氮气含量的增加，不仅总的电弧热功率增加，阳极热功率占整个电弧热功率的比例明显提高。验证了氩氮电弧的高热特性。 直流氩氮保护TIG焊电弧数值模拟的结果表明：随着氮气含量的增加，电弧的温度、电流密度以及等离子体速度均增大，符合实验所测定的氩氮电弧的高热特性。ANSYS强大的矢量图示功能使得对电弧内部离子运动以及各种场的实际分布非常直观。 对直流氩氮TIG焊电弧的模拟为实现焊接过程的虚拟制造奠定了基础，为熔池行为的研究提供了最重要的熔池表面电流密度分布和电弧压力分布的边界条件。更多还原

【Abstract】 N₂-Ar protecting TIG welding arc has been took into accounted for its peculiarity both N₂ protecting TIG welding arc and Ar protecting TIG welding arc and high capacity density. In this article ANSYS software are used to numerical analyze of N₂-Ar protecting TIG welding arc , and electric and thermal peculiarities of arc are proved by experiments at the same time.An axisymmetric mathematical model of N₂-Ar protecting TIG welding arc is developed according to the theory of magnetic fluid dynamics and the welding arc may be defined by fluid dynamics equation and Maxwell equation. Heat transfer and fluid flow of welding arc are analyzed basing on mathematical model.Actual sharp shape of cathode and reasonable boundary conditions and nonlinear character of physical parameter of argon gas and nitrogen gas are adopted in the model. In the model cathode and arc column are conducted together in calculation on electric field, and the assumption method on current distribution density on cathode tip has not been used. Geometry models about electric field, magnetic field and plasma fluid field are developed respectively. Modularization is adopted in ANSYS analysis and the analysis results from these fields are repeatedly called each other until satisfactory level.Elevated temperature method is used to measure the thermal power and electrical properties of welding arc. The result shows that the electric voltage increased with the enhancement of N₂ content, and the calculation on thermal power indicated with the enhancement of N₂ content, not only the total thermal power of arc increased, but also the ratio of anode thermal power to total thermal power increased. This result certified that N₂-Ar protecting TIG welding arc has high thermal power peculiarity.The simulation analysis calculated result shows that with the enhancement of N₂ content, the temperature of arc 、 the current density of arc and the velocity of plasma increased also, and similar with experiment results. The special vector function of ANSYS makes the motion of particle inside arc plasma and the practical distribution of many kind of field very visual.Analyze on N₂-Ar protecting TIG welding arc gives a bases foundation for realizing virtual fabrication and provides important boundary conditions about current density distribution and arc pressure distribution for studying welding pool behavior.更多还原