Dendritic solidification of binary alloys with free and forced convection
Dendritic solidification of binary alloys with free and forced convection
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DOI：
10.1002/fld.988
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发表时间：
2005-09
影响因子：
1.8
通讯作者：
P. Zhao;J. Heinrich;D. R. Poirier
中科院分区：
文献类型：
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作者：
P. Zhao;J. Heinrich;D. R. Poirier
使用锐界面模型在二维空间中模拟由收缩和热溶质浮力驱动的强制对流和自由对流的枝晶凝固。纯物质和合金都被考虑。该模型是使用有限元方法制定的，并直接使用原始变量。使用不同的网格求解耦合能量方程和溶液浓度方程以及不可压缩流的纳维-斯托克斯方程。温度在覆盖整个域（固体+液体）的固定网格中求解，其中使用标记点明确跟踪固液界面。使用符合界面的三角形单元的自适应网格在液体区域中求解浓度和动量方程。速度边界条件直接应用在界面上。该模型通过一系列具有分析、实验和数值结果的问题进行验证。提出了四种模拟：（1）两个小过冷度下的热对流丁二腈晶体生长； (2)枝晶生长成具有均匀强制流动的过冷纯熔体； (3) 纯物质和合金在收缩诱导对流下的等轴枝晶生长； (4) Pb-0.2 wt% Sb 合金在收缩、热和溶质浮力的共同作用下进行对流定向凝固。一些模拟结果与使用其他方法（包括相场法）报告的结果进行了比较；其他都是新的。在每种情况下，都分析了对流对枝晶凝固的影响。版权所有 © 2005 约翰·威利父子有限公司
Dendritic solidification with forced convection and free convection driven by contraction and thermo‐ solutal buoyancy is simulated in two‐dimensional space using a sharp‐interface model. Both pure substances and alloys are considered. The model is formulated using the finite element method and works directly with primitive variables. The coupled energy‐ and solutal concentration‐equations, along with the Navier–Stokes equations for incompressible flow, are solved using different meshes. Temperature is solved in a fixed mesh that covers the whole domain (solid + liquid) where the solid–liquid interface is explicitly tracked using marker points. The concentration and momentum equations are solved in the liquid region using an adaptive mesh of triangular elements that conforms to the interface. The velocity boundary conditions are applied directly on the interface. The model is validated using a series of problems that have analytical, experimental and numerical results. Four simulations are presented: (1) crystal growth of succinonitrile with thermal convection under two small undercoolings; (2) dendritic growth into an undercooled pure melt with a uniform forced flow; (3) equiaxial dendritic growth of a pure substance and an alloy with contraction‐induced convection; and (4) directional solidification of Pb–0.2 wt% Sb alloy with convection driven by the combined action of contraction, thermal and solutal buoyancy. Some of the simulation results are compared to those reported using other methods including the phase‐field method; others are new. In each case, the effects of convection on dendritic solidification are analysed. Copyright © 2005 John Wiley & Sons, Ltd.