The interactive dynamics of flow and directional solidification in a Hele-Shaw cell Part 1. Experimental investigation of parallel shear flow
The interactive dynamics of flow and directional solidification in a Hele-Shaw cell Part 1. Experimental investigation of parallel shear flow
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DOI：
10.1017/s0022112002002033
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发表时间：
2002-10
影响因子：
3.7
通讯作者：
M. Zhang;T. Maxworthy
中科院分区：
文献类型：
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作者：
M. Zhang;T. Maxworthy
人们认识到，熔体中的流动可以对凝固界面的动力学产生深远的影响，从而对凝固材料的质量产生深远的影响。为了更好地理解流体流动对界面形态稳定性以及对胞状和枝晶生长的影响，在水平放置的Hele-Shaw单元中进行了定向凝固实验，其中有和没有外部施加的平行剪切流。使用的样品材料是SCN-1.0重量%丙酮。实验表明，瞬时平行流通过阻尼现有的初始扰动，对平面界面具有稳定作用。平行流破坏了晶胞的左右对称性，使晶胞向来流方向倾斜。倾斜角随速度比的增大而增大。二次枝晶被发现要么不出现或出现在下游侧的晶胞。初始扰动和细胞界面的波长对施加的流动不敏感。
It is recognized that flow in the melt can have a profound influence on the dynamics of a solidifying interface and hence on the quality of the solidified material. To better understand the effect of fluid flow on the interface morphological stability and on the cellular and dendritic growth, directional solidification experiments were carried out in a horizontally placed Hele-Shaw cell with and without externally imposed parallel shear flow. The specimen material used was SCN–1.0 Wt% acetone. The experiment shows that the transient parallel flow has a stabilizing effect on the planar interface by damping the existing initial perturbations. The left–right symmetry of crystal cells was broken by the parallel flow, with cells tilting toward the incoming flow direction. The tilting angle increased with the velocity ratio. The secondary dendrites were found to either not appear or appear much later on the downstream side of the crystal cells. The wavelengths of the initial perturbations and of the cellular interface were insensitive to the imposed flow.