Cz结构浅池内硅熔体热对流的分岔特性

为了了解水平温度梯度作用时Czochralski结构浅池内硅熔体热对流的分岔特性,利用有限差分法进行了非稳态三维数值模拟,坩埚外壁被加热,液池深度为3 mm.模拟结果表明,当逐渐增加温差时,会发生两次流型转变,第一次由二维轴对称流动转变为三维稳态流动,第二次由三维稳态流动转变为热流体波,其可能沿顺时针方向旋转、也可能沿逆时针方向旋转,同时,第二次转变存在分岔现象.

BIFURCATION CHARACTERISTICS OF THERMAL CONVECTION IN A SHALLOW MOLTEN SILICON POOL WITH Cz CONFIGURATION

Three-dimensional numerical simulations of transient thermal convection in a shallow molten silicon pool with Czochralski configuration(depth d=3 mm)have been conducted in this study to understand the bifurcation mechanism of the flow patterns.The crucible sidewall is maintained at constant temperature.The simulation results indicate that two flow transitions occur when radial temperature difference along the free surface increases.At first,the steady two-dimensional flow be- comes steady three-dimensionai flow and then evolves to the hydrothermal wave when the temperature difference is further increased.This hydrothermal wave is characterized by spoke patterns traveling in either the clockwise or counter-clockwise directions,respectively.It is observed that the bifurcation exists in this transition.