Influence of forced flow on the dendritic growth of Fe-C alloy: 3d vs 2d simulation
Influence of forced flow on the dendritic growth of Fe-C alloy: 3d vs 2d simulation
复制标题
强制流动对 Fe-C 合金枝晶生长的影响：3D 与 2D 模拟
DOI：
10.1007/s11663-017-1102-x
复制
发表时间：
2017
影响因子：
3
通讯作者：
Zhu Miaoyong
中科院分区：
文献类型：
--
作者：
Wang Weiling;Wang Zhaohui;Luo Sen;Ji Cheng;Zhu Miaoyong
采用 3D 并行元胞自动机有限体积法 (CA-FVM) 模型模拟了 Fe-0.82 wt pct C 合金在 xy-in-out 和 xyz-in-out 型强制流下的等轴枝晶生长以及在 y-in-out 型强制流下的柱状枝晶生长。此外，还详细讨论和总结了3D和2D模型结果之间的异同。通过分别与边界层校正和 Oseen-Ivanstov 模型进行比较，验证了 3D 和 2D CA-FVM 模型预测强制流动合金枝晶生长的能力。由于强制流可以绕过枝晶的垂直臂，因此垂直臂上游侧的次臂比上游臂上游侧的次臂更加发达，特别是在入口速度较高的情况下。此外，与 xy-in-out 情况相比，下游臂的生长受到较少的抑制，并且在 xyz-in-out 情况下次臂更加发达，因为其尖端周围的侧向流动更大。与 3D 情况相比，2D 等轴树突更加不对称，并且由于溶质包膜较厚而缺乏次生臂。在3D情况下，上游侧（左图）的柱状枝晶得到促进，而中间和下游的枝晶依次受到抑制。然而，在 2D 情况下，顺序抑制从上游侧开始。这主要是因为熔体可以在 3D 空间中绕过上游分支。然而，它只能在二维空间中爬过上游尖端。此外，次级臂显示出上游发展，这随着入口速度的增加而更加显着。次臂的发育水平也受到流动方向上强制流动的衰减的影响。
A 3D parallel cellular automaton-finite volume method (CA-FVM) model was used to simulate the equiaxed dendritic growth of an Fe-0.82 wt pct C alloy with xy-in-out and xyz-in-out type forced flows and the columnar dendritic growth with y-in-out type forced flow. In addition, the similarities and differences between the results of the 3D and 2D models are discussed and summarized in detail. The capabilities of the 3D and 2D CA-FVM models to predict the dendritic growth of the alloy with forced flow are validated through comparison with the boundary layer correction and Oseen–Ivanstov models, respectively. Because the forced flow can pass around perpendicular arms of the dendrites, the secondary arms at the sides upstream from the perpendicular arms are more developed than those on the upstream side of the upstream arms, especially at higher inlet velocities. In addition, compared to the xy-in-out case, the growth of the downstream arms is less inhibited and the secondary arms are more developed in the xyz-in-out case because of the greater lateral flow around their tips. Compared to the 3D case, the 2D equiaxed dendrites are more asymmetrical and lack secondary arms because of the thicker solute envelope. In the 3D case, the columnar dendrites on the upstream side (left one) are promoted, while the middle and downstream dendrites are inhibited in sequence. However, the sequential inhibition starts on the upstream side in the 2D case. This is mainly because the melt can pass around the upstream branch in 3D space. However, it can only climb over the upstream tip in 2D space. Additionally, the secondary arms show upstream development, which is more significant with increasing inlet velocity. The level of development of the secondary arms is also affected by the decay of the forced flow in the flow direction.