热交换法蓝宝石晶体生长的数值模拟研究  

Numerical Simulation Study on Sapphire Crystal Growth by Heat Exchanger Method

作　　者：陈松松[1] 左然[1] 狄晨莹 苏文佳[1] 

机构地区：[1]江苏大学能源与动力工程学院,镇江212013 [2]江苏吉星新材料有限公司,镇江212216

出　　处：《人工晶体学报》2016年第3期590-596,共7页Journal of Synthetic Crystals

基　　金：国家自然科学基金(61474058)

摘　　要：针对热交换法蓝宝石晶体各生长阶段的温场、流场和热应力进行数值模拟研究,并讨论了上部保温层结构、热交换器内管高度对晶体生长的影响。结果表明:长晶初期,固液界面呈椭球形;等径阶段,固液界面平坦,晶体与坩埚壁不接触;长晶后期,中心轴向晶体生长速率增加,晶体中心首先冒出熔体液面。随晶体高度增加,熔体对流由初期的两个涡胞变为等径阶段的一个涡胞,最大对流速度量级为10-3m/s。晶体中最大热应力分布在晶体底部,热应力分布呈W型。增加炉体上部保温层,长晶后期固液界面变得平坦;降低热交换器内管高度,有利于降低晶体底部热应力。Numerical study on sapphire crystal growth by heat exchanger method( HEM) was conducted,with emphasis on the temperature and flow fields and thermal stresses at different growth stages. The influences of top insulation structure and inside tube's height of heat exchanger on sapphire crystal growth were also investigated. The simulation results show that during the initial stage of sapphire crystal growth,the solid-liquid interface shape is ellipsoidal; at the equal-diameter stage,the interface becomes flat without contact with crucible; at the final growth stage,the axial growth rate near the center axis increases,and the center crystal begins to emerge from the melt free surface. With the increase of crystal height,the melt convection changes from two vortexes at the initial stage into one vortex at the equaldiameter stage; the maximum convective velocity is on the order of 10- 3m / s. The maximum thermal stress distributes on the bottom of the crystal,and the thermal stress is distributed as W-shaped. When the upper furnace insulation gets thicker,the solid-liquid interface of final stage becomes flat. By lowering the inside tube 's height of heat exchanger,the thermal stress at the crystal bottom will be reduced.

关 键 词：蓝宝石 晶体生长 热交换法 数值模拟 热应力 

分 类 号：O781[理学—晶体学]