基于Sola算法强迫层流纯物质枝晶生长相场法模拟

Phase-field Simulation of Pure Material Dendritic Growth Based on Sola Algorithm in Force Laminar Flow

采用SIMPLE算法耦合流场的相场法模拟过冷熔体枝晶生长过程计算效率较低。将计算效率较高的自适应压力迭代法修正的Sola算法与相场模型结合,建立模拟过冷熔体在强迫层流状态下枝晶生长的Sola-相场模型(Sola-phase field model,S-PFM),实现过冷熔体流动场与相场的完全耦合,基于该模型模拟高纯丁二腈(SCN)过冷熔体枝晶生长行为。结果表明,过冷熔体在层流状态下,迎流方向枝晶尖端生长速度大于无流动时候的枝晶尖端生长速度,而下游枝晶尖端生长速度小于无流动时候的枝晶尖端生长速度,它与TONG等采用结合SIMPLE算法的相场模型模拟结果一致;并且,流动法向枝晶尖端在其逆流侧出现漩涡初期生长速度不稳定;同时,过冷熔体层流速度越大,迎流方向枝晶尖端生长速度越大,固相率也越高。

Computation efficiency is not high in simulating dendritic growth by combining the SIMPLE algorithm with the phase field method.However,efficient Sola-phase field model（S-PFM） for complete coupling of phase field with flow field of undercooled melt is established to simulate the dendritic growth of udercooled melt in a forced laminar flow state.The model combines the phase field method with the Sola algorithm corrected by adaptive iteration scheme.Based on this model,the dendritic growth behavior of undercooled melt of high purity succinonitrile（SCN） is simulated.The results show that when the undercooled melt is in laminar flow state,the growth velocity of upstream dendritic tip is higher than that when the melt is without flow,but the growth velocity of downstream dendritic tip is lower than that when the melt is without flow.The results agree with the simulation results obtained by TONG and other phase field models which combine with SIMPLE algorithm.Moreover,growth velocity of dendritic tip normal to flow is not stable at the early stage of emergence of eddy current.Besides,the higher the laminar flow rate of undercooled melt is,the higher the growth velocity of upstream dendritic tip and the solid phase ratio will be.