ARTICLE:

• NATURAL CONVECTION OF AIR IN A SHALLOW CYLINDER OF THE ASPECT RATIO THREE UNDER A HIGH MAGNETIC FIELD  download article

S. Maki
Institute of Advanced Material Study, Kyushu University, Kasuga Koen 6-1, Kasuga 816-8580, JAPAN

Toshio Tagawa
Institute of Advanced Material Study, Kyushu University, Kasuga Koen 6-1, Kasuga 816-8580, Japan

Hiroyuki Ozoe
Institute of Advanced Material Study, Kyushu University, Kasuga, Japan; and Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China

ABSTRACT

Natural convection of air in the presence of a vertical magnetic field was studied numerically using a finite difference method. Air was considered since oxygen is a paramagnetic fluid, whose magnetic susceptibility changes with temperature. The distribution of the applied magnetic field was numerically computed by the Biot-Savart's law. The vertical component of the magnetic field takes a maximum value at the central height, and it decreases as the distance from the central height increases. The convection was well suppressed when the enclosure was located in a lower half height under a strong magnetic field, and a quasi-conduction state was attained. This suggests that the apparent gravity can be controlled by using a high magnetic field. Model equations for magnetizing force were derived and numerically computed for Pr = 0.71 and Ra = 2130, and 7100. The magnetic strength is represented by a new parameter, γ = (magnetizing force) / (gravitational force). Here ? =281 ∼ 1169 was studied.

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