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Effect of Axial Magnetic Field on Thermocapillary Convection with Bidirectional Temperature Gradients in a Shallow Annular Pool
Author(s) -
Rao Fei,
Peng Lan
Publication year - 2017
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201600342
Subject(s) - dimensionless quantity , temperature gradient , mechanics , magnetic field , convection , flow (mathematics) , intensity (physics) , materials science , condensed matter physics , optics , physics , meteorology , quantum mechanics
Abstract The thermocapillary convection, which is driven by bidirectional temperature gradients, widely exists in the process of crystal growth and plays an important role in affecting the quality of production. The bidirectional temperature gradients are made up of the temperature difference between inner wall and outer wall along the horizontal direction, the heat flux from the bottom in the vertical direction, and the radiation on the free surface. In this paper, the effect of axial magnetic field on thermocapillary convection with bidirectional temperature gradients was investigated through a series of 3D numerical computations in a shallow annular pool filled with silicon melt. The intensity of axial magnetic field is described by the dimensionless Hartmann number ( Ha ). The results reveal that: both the steady and unsteady flow could be effectively suppressed by the axial magnetic field; With the increasing of Ha , the three‐dimensional steady flow would turn into basic flow; The inhibition effect, which is caused by axial magnetic field, has different performances on two different types of unsteady flow as the further increment in Ha ; In addition, axial magnetic field would increase the value of critical number Q cri , when the horizontal temperature gradient remains unchanged.