Research Initiation: Heat Transfer and Fluid Flow in FusionWelding

本研究是对熔化焊热流体过程的实验和计算研究。这项工作分为三个规模较小、重点明确的调查。第一个是熔化焊接的实验模拟，采用低熔点共晶。将进行详细的温度测量和表面流体流动可视化，以研究涉及相变的多维瞬时传输过程。这一研究将为后续的钨极气体保护焊(GTA)焊接过程的温度测量提供一个起点。将测量铅、铝和钢在GTA焊接过程中不同位置的热历史。为了补充这两项实验研究，还将进行熔焊过程中的传热和流体流动的计算。这项研究的主要目的有两个。首先，寻求对与熔焊相关的热传递和流体流动过程的基本了解。许多复杂的特征，如多维对流和传导输运、相变、表面张力和多种物理机制，以前没有详细讨论过。这些研究还将为焊接工程师提供指导，使热流体过程与焊后机械性能相关联。此外，还将研究在焊接过程中使用热和流体流量测量提供实时纠正措施的可能性。这将允许对自动焊接操作进行实时控制，以提高焊接质量。

This research is an experimental and computational investigation of the thermo-fluid processes associated with fusion welding. The effort is divided into three smaller, clearly focused investigations. The first of these is an experimental simulation of fusion welding, employing a low melting point eutectic. Detailed temperature measurements and surface fluid flow visualizations will be carried out to study the multidimensional, transient transport processes involving phase change. This study will provide a starting point for the subsequent temperature measurements in the gas tungsten arc (GTA) welding process. Thermal histories at various locations during GTA welding will be measured for lead, aluminum and steels. To complement the two experimental studies, computations of heat transfer and fluid flow during fusion welding will also be performed. There are two primary goals of this research. First, a fundamental understanding of the heat transfer and fluid flow processes associated with fusion welding is sought. A number of complex features such as multidimensional convection and conduction transport, change of phase, surface tension and multiple of physical mechanisms which have not previously been considered together in detail. These studies will also provide guidelines to the welding engineer to correlate the thermo-fluid processes with the post weld mechanical properties. In addition, the possibility of providing real time corrective action during welding, using heat and fluid flow measurements will be examined. This will permit real time control of automated welding operations to improve weld quality.