远场来流对过冷熔体中球状晶体生长的影响

Effect of far field flow on the spherical crystal in the undercooled melt

利用渐近分析方法研究了远场来流引起的对流对过冷熔体中球状晶体的生长形态的影响.结果表明,由远场来流导致的对流使得正在生长的球状晶体的界面在向着来流的前部朝来流方向相反的方向生长,并且提高了朝来流的相反方向的生长速度,在背风方向衰减;正在衰减的球状晶体的界面在向着来流的前部加速衰减,在背风方向减缓衰减.

The influence on the growth morphology of the spherical crystal in the undereooled melt imposed by the far field flow is studied by the asymptotic method. It is shown that the far field flow leads to convection in the melt such that the front interface of a growing spherical crystal grows into the undercooled melt in the opposite direction to the flow and enhances the growth rate in the same direction, while the back interface of the growing spherical crystal decays. On the other hand, the front interface of a shrinking spherical crystal further decays, and the back interface of the shrinking spherical crystal decays slower.