中文摘要：

对微下拉法生长YAG晶体进行包括感应加热在内的全局数值模拟,其耦合了感应加热、气体与熔体对流以及固液气三相的热输运,熔体对流同时考虑浮力与表面张力作用.为统一使用有限体积法离散控制方程,采用复函数法求解电磁场,与流函数法对比验证程序正确性.分析整个生长炉内的温度和流场（包括气体和熔体）分布,并针对固液交界面区域温度梯度较小的情况,改进后热器材料,为微下拉法晶体生长炉结构设计提供参考.

英文摘要：

The global numerical simulation was performed for the YAG crystal growth with the micro-pulling-down method. The induction heating,the convection of both gas and melt and the heat transfer of solid/melt/gas were solved simultaneously. In the melt zone,buoyancy convection and thermocapillary flowwere considered. In order to uniformly discretize the controlling equations with the finite volume method,the electromagnetic field was modelled with the complex function method,and the computation of the electromagnetic field was verified with the results from the stream function method. Both the temperature and flowfields in the global furnace（ including gas and melt） were investigated. As for the lowtemperature gradient at the solid-liquid interface,the effects of the afterheater was parametrically investigated. This work is useful for the optimal design of crystal growth furnaces.