PF-LBM Modelling of Dendritic Growth and Motion in an Undercooled Melt of Fe-C Binary Alloy
PF-LBM Modelling of Dendritic Growth and Motion in an Undercooled Melt of Fe-C Binary Alloy
复制标题
Fe-C 二元合金过冷熔体中枝晶生长和运动的 PF-LBM 建模
DOI：
10.1007/s11663-020-01925-6
复制
发表时间：
2020
影响因子：
3
通讯作者：
Zhu Miaoyong
中科院分区：
文献类型：
--
作者：
Luo Sen;Wang Peng;Wang Weiling;Zhu Miaoyong
本文提出了一种二维相场耦合晶格玻尔兹曼法（PF-LBM）来预测Fe-C二元合金熔体中枝晶的生长和运动，其中用相场法（PF）计算枝晶的生长，包括相场和浓度场，用晶格玻尔兹曼法（LBM）计算流场。树突运动由牛顿第二定律决定，在笛卡尔坐标系中由拉格朗日点跟踪。随后，以固体颗粒在停滞流体中的沉降和颗粒在剪切流动中的运动为基准，对模型进行了验证，结果表明，该模型能够预测流体中固体颗粒的运动。最后，利用该模型研究了强流（层流或旋流）条件下枝晶的生长和运动，以及陆地环境下枝晶的沉降。结果表明：当强迫流体为层流时，自由枝晶被驱动平移，枝晶与流动流体的相对速度减小，流体流动对枝晶生长的影响较弱；当强迫流体流动为旋转流体流动时，枝晶在畴中心进行逆时针自旋的离心旋转，旋转半径越来越大。对于陆生环境下枝晶沉降，枝晶与熔体的相对运动促进了枝晶向下的分支生长，抑制了枝晶向上的分支生长，枝晶尾迹区形成了两个涡旋。因此，沉降枝晶表现出明显的不对称形态。
In the present study, a two-dimensional phase field model coupled with Lattice Boltzmann method (PF-LBM) is proposed to predict the dendritic growth and motion in the melt of Fe-C binary alloy, where the phase field method (PF) is used to calculate the dendritic growth, including the phase field and the concentration field, and the lattice Boltzmann method (LBM) is used to calculate the flow field. The dendrite motion is determined by Newton’s Second Law and tracked by Lagrangian point in a Cartesian coordinate system. Later, the model validations were performed with the benchmark of a solid particle settlement in a stagnant fluid and particle motion in a shear flow, and the results show that the present model is capable of predicting the solid particle motion in the fluid flow. Finally, the model is adopted to investigate the dendritic growth and motion in a forced fluid flow (laminar flow or rotational flow), and the dendrite settlement in a terrestrial environment. The results show that when the forced fluid flow is a laminar flow, the free dendrite would be driven to translate, and the relative velocity between the dendrite and flow fluid decreases, resulting in weak influence of fluid flow on the dendritic growth. When the forced fluid flow is a rotational fluid flow, the dendrite would centrifugally rotate on the domain center with a counterclockwise self-spinning, and the rotation radius becomes larger and larger. For the case of dendrite settlement in a terrestrial environment, the relative movement between the dendrite and melt promotes the downward branch growth, but inhibits the upward branch growth, and two vortices form at the wake region of dendrite. Therefore, the settling dendrite shows a significant asymmetrical morphology.