Phase-field simulation of forced flow effect on random preferred growth direction of multiple grains

The random distribution problem of dendrite preferred growth direction was settled by random grid method. This method was used to study the influence of forced laminar flow effect on multiple grains during solidification. Taking high pure succinonitrile (SCN) undercooled melt as an example, the forced laminar flow effect on multiple grains was studied by phase-field model of single grain which coupled with flow equations at non-isothermal condition. The simulation results show that the random grid method can reasonably settle the problem of random distribution and is more effective. When the solid fraction is relatively low, melt particles flow around the downstream side of dendrite, and the flow velocity between two dendrite arms becomes high. At the stage of solidification time less than 1800Δt, every dendrite grows freely; the upstream dendrites are stronger than the downstream ones. The higher the melt flow rate, the higher the solid fraction. However, when the solid fraction is relatively high, the dendrite arm intertwins and only a little residual melt which is not encapsulated can flow; the solid fraction will gradually tend to equal to solid fraction of melt without flow.