摘要：双缆式GMAW是在双丝GMAW的基础上发展起来的节能、高效且优质的焊接方法。本文基于常规流体力学软件FLUENT，开展了双缆式GMAW电弧行为数值模拟，并利用高速摄像系统进行试验验证。首先，建立双缆式GMAW电弧的数值分析模型，通过调节电流、保护气体流量还有双丝间距等焊接参数，考察对电弧温度场、速度场和压力场的影响。结果表明：当焊接电流增大时，双缆式GMAW中的电弧温度场、速度场、压力场均增大，但是变化量同双丝GMAW相比电弧最高温度、速度以及压力场均降低。当保护气体流量增大时，不同于双丝GMAW中电弧温度、等离子流速度以及电弧压力呈现先增大后减小的趋势,双缆式焊丝的电弧形态相对于双丝在电弧中部出现了收缩。当双丝间距增大时，双缆式焊丝GMAW中电弧的最高温度影响并不明显，但是对电弧形态的影响很大，速度场和压力场都是随着双丝间距的增大逐渐较小。试验验证采用高速摄像系统对双缆式电弧进行拍摄，发现和模拟所得的电弧形态大体相同，证明了所建立模型的合理性。

关键词：双丝GMAW、双缆式GMAW、电弧行为、数值分析

Abstract：Double cable GMAW is a double-wire GMAW developed on the basis of energy-saving, efficient and high-quality welding methods.Based on the conventional fluid mechanics software FLUENT, the numerical simulation of double cable GMAW arc behavior is carried out and verified by high speed camera system.Firstly, the numerical analysis model of double cable GMAW arc is established. The influence of current, protection gas flow and double wire spacing on the arc temperature field, velocity field and pressure field are investigated.The results show that the arc temperature field, velocity field and pressure field increase in the double cable GMAW when the welding current increases, but the maximum temperature, velocity and pressure field of the arc are lower than that of the double wire GMAW.When the shielding gas flow increases, unlike the double wire GMAW arc temperature, plasma velocity and arc pressure show the first increase and then reduce the trend of double cable welding arc shape relative to the double wire in the middle of the arc contraction.When the distance between the double wire increases, the maximum temperature of the arc in the double cable welding wire GMAW is not obvious, but it has a great influence on the arc shape. The velocity field and the pressure field are gradually smaller with the increase of the double wire spacing. Experimental results show that the high-speed camera system is used to photograph the double-cable arc, and the results are found to be similar to the simulation results, which proves the rationality of the model.

Key words: Double wire GMAW, Double cable type GMAW, Arc behavior, Numerical analysis

目录

第一章绪论 1

1.1课题背景与意义 1

1.2国内外研究现状 2

1.2.1缆式焊丝研究现状 2

1.2.2双丝焊国内外研究现状 3

1.3主要研究内容 5

第二章FLUENT软件介绍和数值分析 6

2.1FLUENT软件介绍 6

2.1.1FLUENT软件的构成 7

2.1.2求解计算 7

2.2GMAW数值分析模型 9

2.2.1基本假设及控制方程 9

2.2.2双缆式焊丝GMAW电弧数值模型建立 11

2.2.3电弧模型的网格划分