一种用于带对流的多相凝固的新型大势相场格子玻尔兹曼模型
A novel Grand-Potential Phase-Field Lattice-Boltzmann model for multi-phase solidification with convection
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中文总结 AI 辅助
本研究开发耦合大势相场模型与格子玻尔兹曼方法的计算框架，模拟带对流的多相凝固，揭示对流对合金凝固微观结构演化的影响机制。
中文摘要 AI 辅助
熔体对流在合金凝固过程的微观结构演化中起着关键作用，但准确捕捉其与移动固液界面的相互作用仍是一项重大计算挑战，尤其在多相、多组分体系中。本研究开发了一种计算框架，将大势（Grand-Potential）相场模型与格子玻尔兹曼方法（LBM）耦合，以在统一且热力学一致的公式内模拟对流驱动的凝固。所提方法严格在演化的固液界面处施加无滑移条件，流体输运采用标准单弛豫时间Bhatnagar-Gross-Krook碰撞算子求解。该框架为解决界面、溶质输运与流体流动的耦合演化提供了高效且鲁棒的方法。通过对自然对流下枝晶和共晶凝固的模拟，验证了该框架的通用性。结果表明，在两种体系中，对流显著改变溶质偏析、使生长前沿失稳并诱导振荡生长模式。这些实例说明所提方法具备捕捉复杂流动诱导的形态不稳定性的能力，为理解合金凝固中对流驱动微观结构演化的机制提供了新见解。
英文摘要
Melt convection plays a critical role in microstructure evolution during alloy solidification, yet accurately capturing its interaction with moving solid-liquid interfaces remains a significant computational challenge, particularly in multi-phase, multi-component systems. In this work, we develop a computational framework that couples a Grand-Potential phase-field model with the Lattice Boltzmann method (LBM) to simulate convection-driven solidification within a unified and thermodynamically consistent formulation. The proposed approach rigorously enforces no-slip conditions at evolving solid-liquid interfaces, while fluid transport is solved using the standard single-relaxation-time Bhatnagar-Gross-Krook collision operator. The framework provides an efficient and robust methodology for resolving the coupled evolution of interfaces, solute transport, and fluid flow. The versatility of the proposed framework is demonstrated through simulations of dendritic and eutectic solidification under natural convection. The results show that convection significantly modifies solute segregation, destabilizes growth fronts, and induces oscillatory growth modes in both systems. These examples illustrate the capability of the proposed method to capture complex flow-induced morphological instabilities and provide new insights into the mechanisms governing convection-driven microstructure evolution in alloy solidification.
