摘要
针对激光熔覆过程,建立FLUENT三维瞬态熔化-凝固模型,研究由表面张力梯度引起的Marangoni流对熔池温度、温度梯度、熔体冷却速率和流动行为的影响。研究结果表明,激光熔覆区域的温度场基本呈椭圆形分布,且在Marangoni流影响下,熔池内温度、温度梯度和冷却速率均低于无Marangoni流影响下的温度、温度梯度和冷却速率。同时,在Marangoni流影响下,熔池表面的熔体流向为径向向外,形成两个方向相反的涡流,并在表面引发流速奇异双峰现象,即熔池中心流速最小而两侧流速最大。随着熔池深度的增加,流速奇异性逐渐消失。
Aiming at the laser cladding process,a FLUENT three-dimensional transient melt-solidification model was established to investigate the effect of Marangoni convection caused by the surface tension gradient on the temperature,temperature gradient,cooling rate and flow behavior of molten pool.The results show that the temperature field of the laser cladding region is basically elliptical symmetrical.The temperature,temperature gradient and cooling rate of molten pool under the Marangoni effect are lower than the temperature,temperature gradient and cooling rate without Marangoni flow.At the same time,under the influence of Marangoni flow,the melt flow of the molten pool surface is radially outward,forming two vortex loops in opposite directions,which caused the phenomenon of strange double peaks flow on the surface.That is,the center velocity of the molten pool is the smallest and the flow rate on both sides is the largest.As the molten pool depth increases,the velocity singularity gradually disappears.
作者
崔承云
方翠
张文龙
Cui Chengyun;Fang Cui;Zhang Wenlong(School of Mechanical Engineering,Jiangsu University,Zhenjiang,Jiangsu 212013,China)
出处
《应用激光》
CSCD
北大核心
2018年第3期409-416,共8页
Applied Laser
基金
国家自然科学基金资助项目(项目编号:51505198)
江苏省政府留学奖学金资助项目
