A Multiscale 3D Model of the Vacuum Arc Remelting Process
A Multiscale 3D Model of the Vacuum Arc Remelting Process
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DOI：
10.1007/s11661-013-1680-4
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发表时间：
2013-12-01
影响因子：
2.8
通讯作者：
Lee, Peter D.
中科院分区：
文献类型：
--
作者：
Pericleous, Koulis;Djambazov, Georgi;Lee, Peter D.
一个三维的，瞬态的，多尺度模型的VAR过程中，允许新的模拟电弧行为的波动对熔池中的流动和传热的影响，这对微观结构和缺陷的影响。电弧的瞬态行为的特点是使用外部磁场和表面电流的测量，然后被用作瞬态边界条件的模型。采用CFD技术模拟了磁场、湍流金属流和热传递的相互作用，并将该“宏观”模型与微观凝固模型相关联。这允许在枝晶微观结构的瞬态波动进行预测，允许第一个耦合的宏观操作参数和微观结构缺陷之间的三维相关性进行。有人发现，由电弧的运动驱动的对流引起的糊状区的局部重熔，导致在渗透性和溶质密度的变化。这会导致局部瑞利数的变化，从而导致产生斑点凝固缺陷的条件。还模拟了颗粒落入的三维瞬态跟踪，使得能够通过量化进入熔体的夹杂物的轨迹和溶解来预测“白色斑点”缺陷。(C)矿物、金属和材料协会和ASM国际2013
A three-dimensional, transient, multiscale model of the VAR process is presented, allowing novel simulations of the influence of fluctuations in arc behavior on the flow and heat transfer in the molten pool and the effect this has on the microstructure and defects. The transient behavior of the arc was characterized using the external magnetic field and surface current measurements, which were then used as transient boundary conditions in the model. The interactions of the magnetic field, turbulent metal flow, and heat transfer were modeled using CFD techniques and this "macro" model was linked to a microscale solidification model. This allowed the transient fluctuations in the dendritic microstructure to be predicted, allowing the first coupled three-dimensional correlations between macroscopic operational parameters and microstructural defects to be performed. It was found that convection driven by the motion of the arc caused local remelting of the mushy zone, resulting in variations in permeability and solute density. This causes variations in the local Rayleigh number, leading to conditions under which freckle solidification defects will initiate. A three-dimensional transient tracking of particle fall-in was also simulated, enabling predictions of "white spot" defects via quantification of the trajectory and dissolution of inclusions entering the melt. (C) The Minerals, Metals & Materials Society and ASM International 2013