Phase field modeling of lamellar eutectic growth under the influence of fluid flow

Using PF-LBM (phase-field and Lattice-Boltzmann) model, the effects of flow velocity and flow direction on the CBr4-C2Cl6 eutectic 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 velocity u = 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 velocity u = 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 velocity u = 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 velocity u = 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.

The liquid flow direction and flow velocity have significant influence on morphology o f eutectic lamellar growth; without liquid flow, the lamellar growth mode is symmetrical growth mode, which is perpendicular to the solid-liquid interface; With liquid flow, 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.148