Oscillatory Magnetothermal Convection of Non-Ferrous Fluid in a Vertical Cylindrical Enclosure With a Heated Rotating Disk at Bottom Center

Abstract

The non-ferrous fluid is contained in a vertical cylindrical enclosure, which is cooled from both above and side isothermally. The lower end-plate has an isothermally heated disk in the center, while the outer part is thermally insulated. The magnetic gradient generated inside a bore space in a super-conducting magnet as a source of the magnetic force is replaced with that generated by the steady electric current circulating within a single circular electric coil. When the enclosure was installed inside a bore space with the magnetic gradient, our transient three-dimensional numerical computations for a non-ferrous fluid in the enclosure were showed the following numerical results. In the enclosure with the heated static disk at bottom center, when the heated static disk was fixed above the magnetic center, the magnetothermal convection with the symmetric velocity and temperature fields was induced by the magnetic force. The heat transfer rate of magnetothermal convection became larger than that of natural convection. On the other hand, when the heated static disk was fixed below the magnetic center, the magnetothermal convection with the asymmetric velocity and temperature fields was induced by the magnetic force. The heat transfer rate of magnetothermal convection became smaller than that of natural convection. These magnetothermal convections were independent of time. In the enclosure with the heated rotating disk at bottom center, when the heated rotating disk was fixed above the magnetic center, the symmetric magnetothermal convection without the time dependence was also computed. However, when the heated rotating disk was fixed below the magnetic center, the asymmetric magnetothermal convection with the time dependence was computed.