Persistent Current in a Mesoscopic Cylinder: Effects of Radial Magnetic Field

This paper provide two methods to analyze the cogging torque of PM motor with radial magnetic field and parallel magnetic field, FEM method and Analytic method. The FEM model and Analytic model of PM motor with radial magnetic field and parallel magnetic field are founded. We analyze the model in both methods. From the result of analysis. The air-gap magnetic density of PM motor can be analyzed. We can find the cogging torque of radial magnetic field PM motor is much heavily than the cogging torque of parallel magnetic field PM motor. The result of Analytic method is close to the result of FEM method. The Analytic method is useful in analyze the cogging torque of PM motor.

Download Full-text

Magnetohydrodynamic lubrication flow between parallel rotating disks

Journal of Fluid Mechanics ◽

10.1017/s0022112062000464 ◽

1962 ◽

Vol 13 (1) ◽

pp. 21-32 ◽

Cited By ~ 76

Author(s):

W. F. Hughes ◽

R. A. Elco

Keyword(s):

Magnetic Field ◽

Axial Magnetic Field ◽

Load Capacity ◽

Electrical Energy ◽

Axial Current ◽

Frictional Torque ◽

Rotating Disks ◽

Radial Magnetic Field ◽

Electrically Conducting ◽

Parallel Disks

The motion of an electrically conducting, incompressible, viscous fluid in the presence of a magnetic field is analyzed for flow between two parallel disks, one of which rotates at a constant angular velocity. The specific application to liquid metal lubrication in thrust bearings is considered. The two field configurations discussed are: an axial magnetic field with a radial current and a radial magnetic field with an axial current. It is shown that the load capacity of the bearing is dependent on the MHD interactions in the fluid and that the frictional torque on the rotor can be made zero for both field configurations by supplying electrical energy through the electrodes to the fluid.

Download Full-text

Compensation of the radial magnetic field component of solenoids wound with anisotropic Bi(2223)Ag tape

Superconductor Science and Technology ◽

10.1088/0953-2048/10/11/010 ◽

1997 ◽

Vol 10 (11) ◽

pp. 847-852 ◽

Cited By ~ 33

Author(s):

J Pitel ◽

P Kovác

Keyword(s):

Magnetic Field ◽

Field Component ◽

Magnetic Field Component ◽

Radial Magnetic Field

Download Full-text

Combined Marangoni and buoyancy convection in a porous annular cavity filled with Ag-MgO/water hybrid nanofluid

Current Nanoscience ◽

10.2174/1573413717666210928153741 ◽

2021 ◽

Vol 17 ◽

Author(s):

B. Kanimozhi ◽

M. Muthtamilselvan ◽

Qasem M. Al-Mdallal ◽

Bahaaeldin Abdalla

Keyword(s):

Magnetic Field ◽

Stokes Equations ◽

Volume Fraction ◽

Axial Magnetic Field ◽

Vertical Wall ◽

Navier Stokes ◽

Hybrid Nanofluid ◽

Radial Magnetic Field ◽

Navier Stokes Equations ◽

Buoyancy Convection

Background: This article numerically examines the effect of buoyancy and Marangoni convection in a porous enclosure formed by two concentric cylinders filled with Ag-MgO water hybrid nanofluid. The inner wall of the cavity is maintained at a hot temperature and the outer vertical wall is considered to be cold. The adiabatic condition is assumed for other two boundaries. The effect of magnetic field is considered in radial and axial directions. The Brinkman-extended Darcy model has been adopted in the governing equations. Methods: The finite difference scheme is employed to work out the governing Navier-Stokes equations. The numerically simulated outputs are deliberated in terms of isotherms, streamlines, velocityand average Nusselt number profiles for numerous governing parameters. Results: Except for a greater magnitude of axial magnetic field, our results suggest that the rate of thermal transport accelerates as the nanoparticle volume fraction grows.Also, it is observed that there is an escalation in the profile of average Nusselt numberwith an enhancement in Marangoni number. Conclusion: Furthermore, the suppression of heat and fluid flow in the tall annulus is mainly due to the radial magnetic field whereas in shallow annulus, the axial magnetic field profoundly affects the flow field and thermal transfer.

Download Full-text

Torsional waves driven by convection and jets in Earth’s liquid core

Geophysical Journal International ◽

10.1093/gji/ggy416 ◽

2018 ◽

Vol 216 (1) ◽

pp. 123-129 ◽

Cited By ~ 2

Author(s):

R J Teed ◽

C A Jones ◽

S M Tobias

Keyword(s):

Magnetic Field ◽

Density Gradient ◽

Inner Core ◽

Liquid Core ◽

Outer Core ◽

Dynamo Action ◽

Radial Magnetic Field ◽

Torsional Waves ◽

Plausible Mechanism ◽

Rich Liquid

SUMMARY Turbulence and waves in Earth’s iron-rich liquid outer core are believed to be responsible for the generation of the geomagnetic field via dynamo action. When waves break upon the mantle they cause a shift in the rotation rate of Earth’s solid exterior and contribute to variations in the length-of-day on a ∼6-yr timescale. Though the outer core cannot be probed by direct observation, such torsional waves are believed to propagate along Earth’s radial magnetic field, but as yet no self-consistent mechanism for their generation has been determined. Here we provide evidence of a realistic physical excitation mechanism for torsional waves observed in numerical simulations. We find that inefficient convection above and below the solid inner core traps buoyant fluid forming a density gradient between pole and equator, similar to that observed in Earth’s atmosphere. Consequently, a shearing jet stream—a ‘thermal wind’—is formed near the inner core; evidence of such a jet has recently been found. Owing to the sharp density gradient and influence of magnetic field, convection at this location is able to operate with the turnover frequency required to generate waves. Amplified by the jet it then triggers a train of oscillations. Our results demonstrate a plausible mechanism for generating torsional waves under Earth-like conditions and thus further cement their importance for Earth’s core dynamics.

Download Full-text