摘要：优质、高效、低成本是目前材料加工行业对于焊接技术提出的新要求，眼下提高焊接效率的手段主要有添加多丝、添加磁场、添加热源等等，但是这些手段对于焊接设备的提出了很高的要求，因此，双缆式GMAW焊这种成本低、设备简单、操作容易的高效焊接方法应运而生。

本文对于Q235钢建立了基于FLUENT软件的双缆式GMAW焊温度场数学模型，综合考虑了相变潜热、材料热物理性能等问题，对在不同焊接参数下的双缆式GMAW焊接温度场进行模拟计算，比对不同焊接参数下温度场的演变过程，总结出了合适的焊接参数对于温度场的影响规律。最后通过科学的验证方式，用红外热像仪拍摄的温度场、焊缝的宏观形貌和模拟的温度场进行对比研究，证明了本文所建立的数学模型的可靠性。

本文所建立的热源模型是在考虑了多种外界条件后建立的，在结合了后文的实验验证的结果后，所得到的双缆式GMAW焊热源模型具有普遍性和准确性，对于改变实际焊接过程的焊接参数，从而改善焊接质量具有指导作用，也为以后的数值模拟提供有效的焊接热源模型。

关键词：双缆式GMAW焊；数值模拟；温度场；FLUENT

Abstract：At present, the new requirements for welding technology in the material processing industry are high quality, high efficiency and low cost, now improve the efficiency of welding means to add multi-wire, add magnetic field, add heat, etc. , but these means for welding equipment made a very high requirements, therefore, double cable wire GMAW welding which has the advantage of low cost, simple equipment and easy operation came into being.

In this paper, the mathematical model of temperature field of double cable wire GMAW welding is established by using FLUENT software for Q235 steel. The latent heat of phase change and the thermophysical properties of the material are considered. The temperature field of double cable wire GMAW welding under different parameters is simulated and calculated.Comparing the evolution process of temperature field under different welding parameters,and the welding parameters on the effect of temperature field are summarized. Finally, through the scientific verification method, the temperature field, the macro morphology of welding seam and the simulated temperature field are compared by infrared thermal imager, and the reliability of the mathematical model established in this paper is proved.

The heat source model established in this paper is based on the influence of external conditions such as arc deflection, arc driving force and droplet transfer.After combining the results of later experimental verification, the obtained double cable wire GMAW welding The thermal model has the universality and accuracy, which can guide the welding parameters of the actual welding process and improve the performance of the welded joints, and also provide an effective welding heat source model for the future numerical simulation.

Keywords:Double cable wire GMAW welding, Numerical simulation, Temperature field, FLUENT

目  录

第一章 绪论 1

 1.1课题研究背景 1

 1.2双丝焊简介 2

1.2.1双丝焊的分类 2

1.2.2双丝焊的发展历程 3

1.2.3双缆式GMAW焊的优点 4

1.3双缆式GMAW焊数值模拟技术研究进展 5

第二章 双缆式GMAW焊熔池数值模拟理论基础 6

2.1数值方法简介 6

2.2 FLUENT软件包简介 6

2.3流体力学理论基础及传热学理论基础 7

2.4求解器及计算模型的选择 7

2.5数学模型的分析 8

2.6双缆式GMAW熔池计算模型的建立 9

2.6.1双缆式GMAW焊基本热源模型的选取 9

2.6.2热源模型的偏转 9

2.6.3熔滴热源的增加 11

2.6.4双缆式GMAW热源模型的建立 12

2.6.5几何模型的建立与网格划分 13

2.6.6设置材料性能 14