Influence of rotating magnetic field strength on three-dimensional thermocapillary flow in a floating half-zone model

Abstract

The effects of rotating magnetic field (RMF) on the three-dimensional thermocapillary flow of semiconductor melt (Pr = 0.01) in a floating half-zone model under microgravity are investigated numerically by the finite volume method. The results indicate that the thermocapillary flow without magnetic field is a steady three-dimensional convection for Ma = 40 in a floating half-zone model with As = 1, and the convection evolves to an oscillatory three-dimensional flow by applying 1–6 mT RMF with 50 Hz rotating frequency. Based on the fast Fourier transform spectrum, the convection is confirmed to be a periodically oscillating flow, the oscillatory main frequency, 1.59 × 10−3 Hz for 1 mT RMF and 5.84 × 10−2 Hz for 6 mT RMF, increases with the magnetic strength. However, with increasing the magnetic field strength up to 7 mT, the three-dimensional thermocapillary flow is effectively controlled and the convection turns into a steady axisymmetrical one.