Phase field modeling of lamellar eutectic growth under the influence of fluid flow
Phase field modeling of lamellar eutectic growth under the influence of fluid flow
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流体流动影响下层状共晶生长的相场模拟
DOI：
10.1016/j.commatsci.2017.05.035
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发表时间：
2017
影响因子：
3.3
通讯作者：
Jia Bei bei
中科院分区：
文献类型：
--
作者：
Feng Li;Feng Xiao jing;Lu Yang;Zhu Chang sheng;Jia Bei bei
采用PF-LBM（相场和格子-玻尔兹曼）模型，模拟研究了强制流动中流速和流动方向对CBr4-C2Cl6共晶层状生长形貌的影响。结果表明：液体流动方向和流速对共晶层状生长的形貌有显着影响；无液体流动时，层状生长方式为对称生长方式，垂直于固液界面；当流速u=0.005m/s时，当液流方向与Y方向（平行于共晶层状）夹角θ=0°时，液流对共晶生长形貌没有影响；当角度θ=45°、模拟时间t=20,000Δt时，层状生长方式为振荡方式、界面前端β相形核和α层状分支；当角度θ=90°、模拟时间t=40,000Δt时，片层生长方式为共晶层间距振荡方式，向液流方向生长，片层界面不稳定，与β相形核和α相分支耦合；当角度θ=45°、模拟时间t=120,000Δt时，界面前端出现共晶层间距振荡、β相形核和α相分支的复杂生长形貌；当角度θ=90°、模拟时间t=120,000Δt时，保持初始振荡的稳定增长以及β相形核和α相层状分枝的生长模式（当t=40,000Δt时）；与角度θ=90°相比，当角度θ=45°时，由于间距调整，片晶间距减小且片晶对增加的现象较早出现。当夹角θ=90°时，随着流速的增大，层状共晶生长速度加快，且向液流方向生长更加明显；当流速u=0.0m/s（无流场）时，层状生长形态为振荡对称生长模式，垂直于固液界面；当流速u=0.003~0.005 m/s时，层状生长形态为振荡和向液流方向倾斜的混合生长模式；当流速u=0.007–0.009 m/s时，由于β相成核，层状生长形态是界面前部层状间距减小、层状对增加的稳态模式。随着流速的增加，片层形态选择为：垂直于固液界面的共晶层间距对称振荡状态→倾斜生长和层间距振荡不稳定→片层间距振荡β相成核和片层界面前端的α相分支。
Using PF-LBM (phase-field and Lattice-Boltzmann) model, the effects of flow velocity and flow direction on the CBr4-C2Cl6eutectic lamellar growth morphology in the forced flow are simulated and studied. The results show: the liquid flow direction and flow velocity have significant influence on morphology of eutectic lamellar growth; without liquid flow, the lamellar growth mode is symmetrical growth mode, which is perpendicular to the solid-liquid interface; with flow velocityu= 0.005 m/s, when the angle Θ = 0° which between the liquid flow direction and the Y direction (parallel to the eutectic lamellar), liquid flow hasn’t effect on eutectic growth morphology; when the angle Θ = 45°, the simulation time t = 20,000Δt, the lamellar growth mode is the mode of oscillation, the β phase nucleation and the α lamellar branching in the front of interfaces; when the angle Θ = 90°, the simulation time t = 40,000Δt, the lamellar growth mode is the mode of eutectic lamellar spacing oscillation and grows to liquid flow direction, and the interface of the lamellar is not steady, which couples with the β phase nucleation and the α phase branching; when the angle Θ = 45°, the simulation time t = 120,000Δt, the complex growth morphology of eutectic lamellar spacing oscillation, the β phase nucleation and the α phase branching appear in the front of interfaces; when the angle Θ = 90°, the simulation time t = 120,000Δt, the steady growth of the initial oscillation and the growth mode of the β phase nucleation and the α phase lamellar branching (when t = 40,000Δt) are maintained; in contrast to the angle Θ = 90°, when the angle Θ = 45°, the phenomenon of lamellar spacing decreases and lamellar pairs increase earlier appear because of the spacing adjustment. when the angle Θ = 90°, with the increase of the flow velocity, the growth velocity of lamellar eutectic is faster, and growth toward the liquid flow direction is more obvious; when flow velocityu= 0.0 m/s (without flow field), the lamellar growth morphology is the growth pattern of oscillation and symmetry, which is perpendicular to the solid-liquid interface; when flow velocityu= 0.003–0.005 m/s, the lamellar growth morphology is the mixed growth pattern of oscillation and tilting to the liquid flow direction; when flow velocityu= 0.007–0.009 m/s, the lamellar growth morphology is the steady mode of lamellar spacing decreases and lamellar pairs increase in the front of interface because of the β phase nucleation. With the increase of flow velocity, the lamellar morphology selection is: eutectic lamellar spacing symmetrical oscillation state, which is perpendicular to the solid-liquid interface → tilt growth and lamellar spacing oscillatory instability → lamellar spacing oscillation the β phase nucleation and the α phase branching in the front of lamellar interface.