采用全浮区模型数值研究旋转磁场作用下不同辐射加热温度时熔区内热毛细对流流动特性。研究发现，B0=1 mT的旋转磁场产生的洛伦兹力不足以控制熔区中的热毛细对流，熔体内流场呈现周期性旋转振荡特征，振荡频率随辐射温度的增加而减小，并与Ma数成线性关系。当Ma数较小时，温度场主要由扩散作用决定，呈二维轴对称分布；随着Ma数的增加，熔体中的温度场受对流影响，亦呈周期性振荡，且振荡主频与对流振荡主频相同。保持旋转磁场的频率不变，适当增加磁场强度，熔体内的三维振荡流将转变为准二维的旋转轴对称流，热毛细对流关于中截面镜面对称。对于Ma=21.8、32.9和43.7的熔体，分别施加2、3和5 mT的旋转磁场，熔体中的温度及速度波动被有效抑制。
Through numerical simulation on a full floating-zone, the characteristics of thermocapillary convection in the melt are studied at different radiation heating temperatures under the rotating magnetic fields (RMF). The Lorentz force induced by the applied RMF under 1mT with 50Hz is not sufficient to effectively control the thermocapillary flow. In this case, the thermocapillary flow presents a rotating oscillatory three-dimensional convection with an oscillatory frequency decreasing with radiation temperature and varying linearly with Ma number. The temperature field in the melt has a 2-D steady axisymmetric distribution which is mainly determined by the diffusion effect when the Ma number is relatively small. However, at the relatively large Ma number, the temperature of the melt is influenced by flow and exhibits periodic oscillation with the same frequency of melt convection. By fixing RMF frequency at 50Hz and increasing the magnetic field intensity, the flow in melt turns into a quasi-2D rotating axisymmetric flow from a 3D periodic oscillatory convection. Accordingly the thermocapillary convection presents a mirror-symmetry structure about the middle plane. Both the temperature and velocity fluctuation in the melts with Ma=21.8,32.9,and 43.7 are effectively suppressed under 2, 3, and 5mT RMFs, respectively.
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