多晶硅定向凝固过程中热电磁流动的数值模拟

Numerical Simulation of Thermoelectromagnetic Convection During Direction Solidification of Polysilicon

采用基于有限元分析方法的COMSOL 4.3a多物理场仿真软件,模拟了稳恒磁场作用下,硅熔体在多晶硅定向凝固过程中热电磁流动的变化规律。结果表明,当0≤B<0.4T时,硅熔体流动区域以及平均流速随着磁感应强度的增大而增大,磁场对硅熔体的流动起促进作用;当磁感应强度为0.4T时,平均流速最大值为60.15μm/s,硅熔体流动能力最强;当0.4T<B≤1.0T时,硅熔体的流动区域以及平均流速随着磁场的增大而减小。相比增长阶段,下降幅度较快,磁场对硅熔体的流动抑制作用明显。根据热电磁流体动力学理论阐明了热电磁力和电磁力对热电磁流动的影响。

The change behavior of thermoelectromagnetic convection in silicon melt under the steady magnetic field during direction solidification of polysilicon was simulated by COMSOL Multiphysics version4.3abased on finite element method（FEM）.The results show that with 0≤B〈0.4T,the flow region of silicon melt and average flow velocity are increased with increasing in the magnetic flux intensity.The magnetic field plays a promoting role in the flow of silicon melt.When the magnetic field intensity reaches 0.4T,the maximum of the average velocity in silicon melt is 60.15μm/s.With 0.4T〈B≤1.0T,the flow region of silicon melt and average flow velocity are decreased with increasing in magnetic flux intensity,which is declined quickly compared with growth stage of flow.The inhibitory effect of the magnetic field on the flow rate of silicon melt exhibits obvious.Finally,influence of the thermoelectric magnetic force and electromagnetic force on the thermoelectromagnetic convection in silicon melt was described according to the theory of thermoelectric magnetohydrodynamic.