A computational fluid dynamics approach is used to analyse the influence of beam shaping in fusion welding on melt thermal flow. Three beam shapes are studied at several welding travel speeds: a reference Gaussian profile and its elliptic elongations along and transverse to the welding travel direction. It is found that these beam shapes change not only the intensity and direction of the melt thermocapillary flow but also the flow pattern. For instance, and contrary to the other profiles, the beam shape elongated along the welding travel direction generates melt front vortices that assist metal pre-heating. It can result in deeper penetration, larger melt volume, and lower amount of thermal energy diffused into the heat affected zone. The simple elongation of a beam profile has thus a non-linear effect on the melt flow and in turn on the seam geometry as well as the temperature gradients in the heat affected zone.

计算流体动力学方法用于分析熔焊中的束成形对熔体热流的影响。在几种焊接行进速度下研究了三种光束形状：参考高斯轮廓及其沿和垂直于焊接行进方向的椭圆伸长率。发现这些束形状不仅改变了熔体热毛细流的强度和方向，而且改变了流型。例如，与其他轮廓相反，沿焊接行进方向拉长的光束形状会产生有助于金属预热的熔化前涡流。它可以导致更深的渗透，更大的熔体体积以及更少的散布到热影响区中的热能。