Effects of the Flow Speed on Dendritic Growth in Phase-Field Simulation of Binary Alloy with Convection
A phase-field approach which incorporates mass and momentum and solute conservation equations for simulation of Al-Si binary alloy solidification is studied. The effect of force flow on the dendrite growth and solute profile during the solidification of binary alloy were investigated. The results indicate that dendritic grows unsymmetrically under a forced flow, the growth velocity of the upstream tip is faster than the downstream tip. With the force flow, the upstream tip grows faster due the thinner solute boundary layer. The solute gradient in the solid/liquid interface regions of the upstream tip is higher than that of the downstream tip. The faster the flow velocity, the greater the solute gradients in the solid/liquid interface regions of the upstream tip, the thinner the diffusion layer before the upstream tip. The downstream tip is opposed to the upstream tip. The simulations agree qualitatively with the solidification theoretical results.