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为了研究几何因素和轴向磁场对分离结晶过程中熔体浮力-热毛细对流的影响,采用有限差分法进行三维数值模拟。结果表明,当Marangoni数较小时,熔体内部流动为稳态浮力-热毛细对流;随着Marangoni数的增大并超过一定值,稳态流动转变为非稳态浮力-热毛细对流。随着熔体高度的增加,熔体内部流动先增强后减弱;随着狭缝宽度的减小,熔体流动增强。采用轴向磁场能够有效抑制熔体内浮力热-毛细对流,随着磁场强度的增加,抑制效果逐渐增强。流动失稳的临界Marangoni数随着熔体高度的增加而略有增大,随着狭缝宽度的减小而增大,随着磁场强度的增大而增大。
In order to study the influence of geometric factors and axial magnetic field on melt buoyancy-hot capillary convection in the process of separation and crystallization, a three-dimensional numerical simulation using finite difference method was carried out. The results show that when the Marangoni number is small, the internal flow in the melt is steady-state buoyant-thermocapillary convection. As the Marangoni number increases and exceeds a certain value, the steady-state flow transforms into unsteady buoyant-thermocapillary convection. With the increase of the melt height, the flow inside the melt first increases and then decreases; as the slit width decreases, the melt flow increases. The use of axial magnetic field can effectively restrain the buoyant thermal-capillary convection in the melt. With the increase of magnetic field strength, the suppression effect is gradually enhanced. The critical Marangoni number of flow instability increases slightly with the increase of melt height, increases with the decrease of slit width and increases with the increase of magnetic field.