应用连续性方法模拟枝晶生长

MODELLING OF THE DENDRITE GROWTH BY USING CONTINUOUS METHOD

为了能够从微观尺度上准确的描述凝固过程中枝晶生长情况,采用连续性模型使界面区域内的物理性质不连续现象变成连续型过渡,此外在界面区域内用平均溶质浓度来保证溶质守恒.模拟结果表明这种方法能够很好的处理固/液两相物理性质的差异,显示凝固过程中枝晶的生长、界面失稳、二次校晶臂、三次枝晶臂的演化和显微偏析.

In order to precisely describe the dendrite evolution during solidification process, especially in the micro-scale, a continuous model is adopted to solve the discontinuous physical properties between solid and liquid phases. In this model the physical properties in the interface zone are the average physical properties of solid phase and liquid phase, which can smooth their properties gap and make the properties continuous from liquid to solid phases. In addition, the averaged solute concentration is used to keep the solute conservation in the local interface zone. The simulated results show that this model can deal with the properties gap between the solid and liquid phases in the interface zone, and further simulate the dendritic growth, local interface instability, and appearance of the second dendrite arm, tertiary dendrite arm and the pattern of micro-segregation.