在强加来流作用下二元系中枝晶生长的稳态解

Steady solution of dendritic growth in a binary mixture with imposed flow

  • 摘要: 研究了远场来流作用下二元系中的枝晶生长.当Schmidt数很大时,应用渐近分析方法得到枝晶稳态生长的渐近解,其温度场和浓度场的首级解、一级解均为相似性解,枝晶形状为存在细微波动的旋转抛物面.远场来流的强弱影响着枝晶生长的Peclet数的大小,进而影响着枝晶的尖端半径与生长速度.当过冷度一定时,在枝晶尖端或在枝晶前沿处的温度随着流场的增大而减小,而溶质浓度随着流场的增大而增大.

     

    Abstract: Dendritic growth in a binary mixture with imposed flow was investigated. When the Schmidt number was large, the asymptotic solution for the steady state was obtained by using the asymptotic analysis method. The zeroth-order and the first-order solutions are similar for the temperature and concentration fields. The shape of the dendrite is paraboloid of revolution on which there are small waves. The strength of external flow has a significant effect on the Peclet number of dendritic growth, the tip radius of den-drite and the tip growth velocity. For the given undercooling, the temperature at the dendritic tip or in front of the dendrite decreases with increasing flow, but the solute concentration increases.

     

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