局部干法焊接排水罩的流场分析与优化设计

Flow Field Analysis and Optimized Design of Local Drain Cover in Local Dry Method Welding

在水下焊接方法中,局部干法焊接采用排水罩将焊接区域的水排开进行焊接,接头质量容易保证,无需大型排水设备,易于实现水下焊接自动化。然而,横向焊接时熔池在重力作用下产生下榻,影响焊缝成形。局部干法水下横向焊接时,通过优化排水罩结构,使排水罩内高压气体在排水的同时,产生稳定向上的风场吹袭熔池,抑制熔池下淌,并将焊接产生的烟雾迅速带出排水罩,将大幅提高焊接质量。文中采用数值模拟的方法,研究了排水罩内的湍流气体的风场结构,优化了微型排水罩进气口位置、内部结构。研究发现:由端面进气,在排水罩内加挡板,并采用多孔隔板时可以产生理想的风场。

In the underwater welding method,local dry welding method spreads the water out of weld zone using local drain cover, so it is easy to implement the automation of underwater welding and guarantee the joints quality without large-scale drainage equipment. However, molten welding pool drops because of gravity in horizontal welding, which can affect the appearance of weld seam. For the local dry method horizontal underwater welding, the quality of welding drastically improves by optimizing the internal structure of local drain cover, resulting in a stable upward wind field blowing the pool and preventing the drip of molten pool while pushing out the water in the local drain cover fast. Using simulation method, the wind field structure of turbulent gas in the cover was studied, then,the inlet and internal structure of the miniatrue local drain cover were optimized. It can be found that by air intake from end face, with a baffle and porous barrier in the local drain cover,a perfect wind field appears.