Abstract A continuum mixture model is proposed for phase change of binary alloy including the effect of thermal anisotropy. Thermal anisotropy is incorporated by an additional departure source in the conventional isotropic heat transfer-based energy equation. The governing equations for heat, mass, momentum, and species transport are solved using implicit finite volume method. The pressure and velocity in the momentum equation are coupled using SIMPLER algorithm. The solute mixture concentration is updated using two commonly used methods, the lever rule model and the Scheil rule model. A comprehensive study is made to investigate the effect of thermal anisotropy on solidification physics and final macrosegregation pattern after complete solidification for two cases: one with three sides of the enclosure insulated where planar front generates and the other with two opposite sides insulated where irregular front evolves. The directional effect of thermal anisotropy ratio (AR) on binary alloy phase change behavior has been investigated in detail.

中文翻译：

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二元合金凝固中的热各向异性：等效各向同性模型

摘要 提出了一种包含热各向异性影响的二元合金相变的连续混合模型。热各向异性由一个额外的离场源合并到传统的基于各向同性传热的能量方程中。热量、质量、动量和物质传输的控制方程使用隐式有限体积方法求解。动量方程中的压力和速度使用 SIMPLER 算法耦合。使用两种常用方法更新溶质混合物浓度，杠杆规则模型和 Scheil 规则模型。综合研究了两种情况下热各向异性对凝固物理和最终宏观偏析模式的影响：一个外壳的三个侧面在产生平面前部的地方绝缘，另一个有两个相对的侧面在不规则前部演变的地方绝缘。已经详细研究了热各向异性比 (AR) 对二元合金相变行为的方向性影响。