转晶法KDP单晶生长晶面溶质浓度场模拟

Numerical Simulations of Solute Distribution on the Crystal Surface for Growth of KDP Single Crystal by Rotating-crystal Method

针对转晶法生长KDP单晶过程,进行了流动与物质输运数值模拟,以获得生长过程中晶面溶质浓度(过饱和度)的变化规律。文中展示了晶体表面浓度分布随时间的变化过程;分析了不同转速和晶体尺寸,对晶面时均浓度场的影响。结果表明,转速越快,晶体表面过饱和度越高;晶体尺寸对其表面过饱和度的大小和分布也有较大影响。此外,由于空间上不对称,Z向和Y向晶面过饱和度分布有较大差异。在晶体处于静止或低转速,自然对流可能会对晶体表面的过饱和度分布产生影响。

Numerical simulations of flow and mass transfer were carried out to obtain the solute concentration （supersaturation） distribution of crystal surface in the growth process of potassium dihydrogen phosphate （KDP） single crystals by rotating-crystal method. The temporal variation of surface concentration fields was presented. Time-averaged field of surface supersaturation was introduced and its dependence on rotation rate and crystal size was discussed in detail. The results show that an increase of rotation rate resulted in a distinct increase in surface supersaturation; the magnitude of supersaturation and its homogeneity of distribution were also closely connected to crystal size. The crystal faces that were called Z-axis and Y-axis crystal surface showed a large difference in supersaturation distribution due to the spatial asymmetry. The distribution of surface supersaturation could be influenced by the natural convection when the crystal was stagnant or with a lower rotation rate.