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矩形光斑是宽带激光熔覆的常用热源。根据矩形光斑扫描过的熔覆层呈现上厚下薄的“双椭圆”形状,提出了椭圆热源模型,在FLUENT软件平台上建立了基于椭圆热源的三维瞬态激光熔覆温度场和流场计算模型。模拟结果表明,由于椭圆热源中间高、边缘低的热流分布特点和热量的累积效应,温度场分布具有后拖现象,熔池后端较宽,中部较深。流体速度矢量在熔池中部主要分布在纵截面内,越靠近边缘,在横截面分量越多,且纵截面内较大的涡流位于熔池后方。模拟的熔池整体上呈中间粗、两端细的狭长形貌,与矩形光斑作用下的实际激光熔覆熔池形貌基本吻合。
Rectangular spot is a common heat source for broadband laser cladding. The elliptical heat source model was proposed based on the “thin oval” shape of the cladding layer scanned by the rectangular spot, and the temperature field and flow of the three-dimensional transient laser cladding based on the oval heat source were established on the FLUENT software platform Field Calculation Model. The simulation results show that the distribution of temperature field has the phenomenon of post-drag due to the distribution characteristics of heat flow and the low heat flow in the middle of the ellipse heat source. The back end of the weld pool is wide and the middle part is deep. The fluid velocity vector is mainly distributed in the longitudinal section in the middle part of the weld pool. The closer to the edge, the larger the cross-section component and the larger vortex in the longitudinal section lie behind the weld pool. The simulated weld pool is generally thick in the middle and narrow at both ends, which is basically consistent with the shape of the actual laser cladded weld pool under the action of a rectangular spot.