2219铝合金电子束焊接匙孔演变过程的数值模拟

文中主要借助Fluent软件,基于有限体积离散方法建立了2219铝合金电子束点焊熔池传热、流动和匙孔演变的二维耦合数学模型.在模型中,考虑了表面张力、Marangoni剪切力、流体静压力、金属蒸气反冲压力的作用,并采用VOF(volume of fluid)方法跟踪了匙孔的形成与演变过程.结果表明,反冲压力钻取和涡旋输运的综合作用是匙孔加深的根本原因;沿深度方向热源功率密度的降低会导致前者钻取速度的减小.铝合金的点焊工艺试验表明,数值计算结果与实际吻合较好.

Numerical simulation of keyhole evolution for 2219 aluminum alloy electron beam spot welding process

In this paper, a two-dimensional coupled mathematical model for heat transfer and flow of 2219 aluminum alloy electron beam welding pool was established based on finite volume method in Fluent software. In the model, the effects of surface tension, Marangoni shear force, hydrostatic pressure of fluid and recoil pressure of metal vapor were considered. In addition, formation and evolution of keyhole was traced by VOF (Volume of Fluid) algorithm. The results showed that the primary reason for the deepening of keyhole was the combination of recoil pressure''s drilling and vortex''s transportation. The decreasing heat source''s power density caused the decreasing drilling velocity of recoil pressure. In addition, aluminum alloy spot welding experiment indicated that the numerical simulation result agreed well with the actual one.