Magnetohydrodynamic lubrication flow between parallel rotating disks

1962 ◽  
Vol 13 (1) ◽  
pp. 21-32 ◽  
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.

Inertia Effects in MHD Hydrostatic Thrust Bearing

1969 ◽  
Vol 91 (4) ◽  
pp. 589-596 ◽  
Author(s):  
S. Kamiyama
Keyword(s):  
Analytical Study ◽  
Good Accuracy ◽  
Thrust Bearing ◽  
Axial Magnetic Field ◽  
Load Capacity ◽  
Frictional Torque ◽  
Inertia Effects ◽  
Rotating Speed ◽  
Parallel Disks ◽  
Limiting Case

An approximate analytical study is made of inertia effects in magnetohydrodynamic lubrication flow between two parallel disks, one of which rotates at a constant angular velocity in an axial magnetic field. Fairly good accuracy of the approximate solution is confirmed in the special limiting case of zero rotating speed. By the numerical examples, the inertia effects on pressure distribution, load capacity, and frictional torque of the bearing are clearly shown.

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

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.

Stability of the Base Flow to Axisymmetric and Plane-Polar Disturbances in an Electrically Driven Flow Between Infinitely-Long, Concentric Cylinders

2000 ◽  
Vol 123 (1) ◽  
pp. 31-42
Author(s):  
J. Liu ◽  
G. Talmage ◽  
J. S. Walker
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Axial Magnetic Field ◽  
Normal Modes ◽  
Azimuthal Velocity ◽  
Base Flow ◽  
Transition To Turbulence ◽  
Electrically Conducting ◽  
Concentric Cylinders ◽  
The Stability

The method of normal modes is used to examine the stability of an azimuthal base flow to both axisymmetric and plane-polar disturbances for an electrically conducting fluid confined between stationary, concentric, infinitely-long cylinders. An electric potential difference exists between the two cylinder walls and drives a radial electric current. Without a magnetic field, this flow remains stationary. However, if an axial magnetic field is applied, then the interaction between the radial electric current and the magnetic field gives rise to an azimuthal electromagnetic body force which drives an azimuthal velocity. Infinitesimal axisymmetric disturbances lead to an instability in the base flow. Infinitesimal plane-polar disturbances do not appear to destabilize the base flow until shear-flow transition to turbulence.

THE STAEILITY OF COUETTE FLOW IN AN AXIAL MAGNETIC FIELD

1958 ◽  
Vol 36 (11) ◽  
pp. 1509-1525 ◽  
Author(s):  
E. R. Niblett
Keyword(s):  
Magnetic Field ◽  
Boundary Conditions ◽  
Theoretical Prediction ◽  
Viscous Flow ◽  
Rotation Speed ◽  
Axial Magnetic Field ◽  
Radioactive Isotopes ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
The Stability

Chandrasekhar's theory of the stability of viscous flow of an electrically conducting fluid between coaxial rotating cylinders with perfectly conducting walls is extended to include the case of non-conducting walls, and it is found that their effect is to reduce the critical Taylor numbers and increase the wavelength of the instability patterns by considerable amounts. An experiment designed to measure the values of magnetic field and rotation speed at the onset of instability in mercury between perspex cylinders is described. The radioactive isotopes Hg197 and Hg203 were used to trace the flow. The results support the theoretical prediction that the boundary conditions can have a large effect on the motion.

On the Influence of Finite Wall Conductance and Inertia Effects of Hydrostatic Thrust Bearing

1978 ◽  
Vol 100 (2) ◽  
pp. 271-278
Author(s):  
V. K. Kapur ◽  
Kamlesh Verma
Keyword(s):  
Analytical Study ◽  
Thrust Bearing ◽  
Necessary Conditions ◽  
Axial Magnetic Field ◽  
Constant Angular Velocity ◽  
Frictional Torque ◽  
Load Carrying Capacity ◽  
Inertia Effects ◽  
Parallel Disks ◽  
Load Carrying

An analytical study is presented on the influence of finite wall conductance and inertia effects in magnetohydrodynamic lubrication flow between two parallel disks, one of which is rotating with constant angular velocity, in the presence of the axial magnetic field. Numerical results showing the behavior of wall conductance and inertia effects on pressure distribution, load carrying capacity, critical speed, and frictional torque of the bearing are obtained. Results obtained will provide necessary conditions for wall materials to improve the bearing performance.

The effect of a radial magnetic field on the stability of Couette flow

1994 ◽  
Vol 72 (5-6) ◽  
pp. 258-265 ◽  
Author(s):  
M. A. Ali
Keyword(s):  
Magnetic Field ◽  
Eigenvalue Problem ◽  
Incompressible Fluid ◽  
Couette Flow ◽  
Wave Number ◽  
Rotating Cylinders ◽  
Radial Magnetic Field ◽  
Electrically Conducting ◽  
Angular Velocities ◽  
The Stability

The effect of a radial magnetic field on the stability of an electrically conducting incompressible fluid between two concentric rotating cylinders is considered. The eigenvalue problem for determining the critical Taylor number TC and the corresponding wave number aC is solved numerically for different values of ±μ(= Ω2/Ω1), (where Ω1, and Ω2 are me angular velocities of the inner and outer cylinders, respectively) and for different gap sizes. It is observed that the radial magnetic field stabilizes the flow. This effect is more pronounced for cylinders that are corotating as compared with counter-rotating cylinders or the situation where only the inner one is rotating.

Investigation of DC Vacuum Arc Interruption Ability with Combined Axial and Radial Magnetic Field

2012 ◽  
Vol 516-517 ◽  
pp. 1791-1797 ◽  
Author(s):  
Mohmmad Al Dweikat ◽  
Yu Long Huang ◽  
Xiao Lin Shen ◽  
Wei Dong Liu
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Vacuum Arc ◽  
Axial Component ◽  
Circuit Breakers ◽  
Radial Magnetic Field ◽  
Vacuum Interrupter ◽  
Magnetic Field Simulation ◽  
The Magnetic Field ◽  
Field Influence

DC Vacuum Circuit Breakers based arc control has been a major topic in the last few decades. Understanding vacuum arc (VA) gives the ability to improve vacuum circuit breakers capacity. In this paper, the interaction of a DC vacuum arc with a combined Axial-Radial magnetic field was investigated. The proposed system contains an external coil to produce axial magnetic field (AMF) across the vacuum chamber. The vacuum interrupter (VI) contacts were assumed to be untreated radial magnetic field (RMF) contacts. For this purpose, Finite Element Method (FEM) based Multiphysics simulation of the immerging magnetic field influence on the VA is presented. The simulation shown the ability of the presented system to deflect high DC vacuum arc, also reveals that the vacuum arc interruption capability increases with the rise of the axial component of the magnetic field. Simulation results shown that this method can be applied to improve the interruption capability of the VI.

scholarly journals Thermal diffusion in a binary fluid mixture flows due to a rotating disc of uniform high suction in presence of a weak axial magnetic field

2010 ◽  
Vol 37 (3) ◽  
pp. 161-187
Author(s):  
B.R. Sharma ◽  
R.N. Singh
Keyword(s):  
Magnetic Field ◽  
Axial Magnetic Field ◽  
Rotating Disc ◽  
Fluid Mixture ◽  
Suction Parameter ◽  
Electrically Conducting ◽  
Flow Parameters ◽  
Polar Coordinate ◽  
Dimensional Parameters ◽  
High Suction

The effect of a weak uniform axial magnetic field on separation of a binary mixture of incompressible viscous thermally and electrically conducting fluids flowing due to a rotating disc of uniform high suction is examined. Neglecting the induced electric field the equations governing the motion, temperature and concentration are solved in cylindrical polar coordinate by expanding the flow parameters as well as the temperature and the concentration in powers of suction parameter. The solution obtained for concentration distribution is plotted against the different axial distances from the disc for various values of non-dimensional parameters. It is found that the temperature gradient, axial magnetic field, Reynolds number, Schmidt number, Prandtl number and suction parameter effect the species separation significantly.

Magnetohydrodynamic Effects in Composite Bearings

1967 ◽  
Vol 89 (3) ◽  
pp. 323-328 ◽  
Author(s):  
J. Prakash
Keyword(s):  
Hartmann Number ◽  
Load Capacity ◽  
Short Circuit ◽  
Electrical Energy ◽  
Open Circuit ◽  
Slider Bearing ◽  
Frictional Drag ◽  
Electrically Conducting ◽  
Open Circuit Condition ◽  
Composite Bearing

A theoretical analysis is made of a composite slider bearing using an electrically conducting lubricant such as a liquid metal in the presence of a magnetic field applied perpendicular to the bearing surfaces. Two solutions are presented for large and small values of Hartmann number. It is found that for large Hartmann number significant increase in load capacity can be obtained even under open circuit condition. Short circuit condition results in zero load capacity, under the approximation considered. At small Hartmann number only a slight increase occurs under open circuit condition and external power must be supplied to get a significant increase. It is seen that a magnetohydrodynamic composite bearing does not always give an increase in load capacity as compared to an equivalent inclined slider bearing, as is the case with classical composite bearing. There is a critical Hartmann number depending on the parameters of the problem, above which MHD effects reduce the load capacity as compared to the case of an equivalent inclined slider bearing. It is also observed that the frictional drag on the bearing can be made zero by supplying electrical energy through the electrodes to the fluid.

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