THE MAGNETIC TORQUE EXERTED ON A FINITE CYLINDRICAL CONDUCTOR SLAB BY A "ROTATING" MAGNETIC FIELD

1963 ◽  
Vol 41 (2) ◽  
pp. 384-390
Author(s):  
L. L. Lengyel
Keyword(s):  
Magnetic Field ◽  
Perturbation Technique ◽  
Three Dimensional ◽  
Field Vector ◽  
Rotating Magnetic Field ◽  
End Effects ◽  
Cylindrical Conductor ◽  
Flux Lines ◽  
Magnetic Flux Lines ◽  
Magnetic Induction Field

A cylindrical conductor of finite length revolves slowly in a magnetic field given by a constant, rotating field vector. The magnetic flux lines are normal to the axis of the cylinder. The induced axial currents are deflected at the ends of the conductor slab, and a three-dimensional, antisymmetric current distribution results. A perturbation technique is applied to the nondimensional equations defining the electromagnetic field and force distributions. The zeroth-order solution corresponding to an unperturbed magnetic induction field is carried out in detail. The end effects are found to be substantial if the length to diameter ratio is less than 5.

Application of Alternating Rotating Magnetic Field to Electromagnetic Barrel Finishing

2012 ◽  
Vol 723 ◽  
pp. 466-470
Author(s):  
Z.Q. Liu ◽  
Y. Chen ◽  
J. Teng
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Rotating Magnetic Field ◽  
Magnetic Flux Density ◽  
Distribution Law ◽  
Flux Lines ◽  
Magnetic Flux Lines ◽  
Working Principle ◽  
Barrel Finishing ◽  
The Magnetic Field

The working principle of the electromagnetic barrel finishing machine as well as the generating mechanism and effect of the alternating rotating magnetic field are analyzed, based on the electromagnetic theory to establish a mathematical model of the rotating magnetic field, by the ANSYS finite-element method, resolved the effect of the magnetic flux density and magnetic field strength impacted on the grinding pressure, the electromagnetic finishing machine internal magnetic flux lines distribution law is analyzed under the influence of the alternating rotating magnetic field, finally the reasonableness of the magnetic field distribution is verified by experiments and the electromagnetic finishing machine has been optimized.

scholarly journals Effect of Aerosil and Oleic Acid on Sedimentation of Magnetorheological Fluid

2019 ◽  
Vol 8 (12S2) ◽  
pp. 79-83
Keyword(s):  
Magnetic Field ◽  
Oleic Acid ◽  
Magnetic Force ◽  
Particle Concentration ◽  
Nano Particles ◽  
Carrier Fluid ◽  
Flux Lines ◽  
Smart Fluids ◽  
Magnetic Flux Lines ◽  
Ferro Magnetic

Magnetorheological Fluids (MRFs) are considered as smart fluids because they control viscosity using external magnetic field. It contains ferro-magnetic powder which are aligned in magnetic flux lines. The magnetic force between particles are controlled by magnetic field intensity. This controllable viscosity makes them acceptable in many mechanical applications, but due to difference in density between suspended particles and carrier fluid sedimentation is bound to occur. This thus creates the need of some additives. In our study, silica Nano particles (commercially known as Aerosil 200) is used as stabilizer and Oleic Acid is used as surfactant and their effect on sedimentation is studied in this article. Some other synthesis parameters like particle concentration, stirring duration and material loading also cause some change in sedimentation rate.

scholarly journals Magnetic micro-droplet in rotating field: numerical simulation and comparison with experiment

2017 ◽  
Vol 821 ◽  
pp. 266-295 ◽  
Author(s):  
J. Erdmanis ◽  
G. Kitenbergs ◽  
R. Perzynski ◽  
A. Cēbers
Keyword(s):  
Magnetic Field ◽  
Boundary Integral Equations ◽  
Three Dimensional ◽  
Dipolar Interaction ◽  
Boundary Integral ◽  
Rotating Magnetic Field ◽  
Three Dimensions ◽  
Triaxial Ellipsoid ◽  
Equilibrium Shapes ◽  
Magnetic Droplet

Magnetic droplets obtained by induced phase separation in a magnetic colloid show a large variety of shapes when exposed to an external field. However, the description of the shapes is often limited. Here, we formulate an algorithm based on three-dimensional boundary-integral equations for strongly magnetic droplets in a high-frequency rotating magnetic field, allowing us to find their figures of equilibrium in three dimensions. The algorithm is justified by a series of comparisons with known analytical results. We compare the calculated equilibrium shapes with experimental observations and find a good agreement. The main features of these observations are the oblate–prolate transition, the flattening of prolate shapes with the increase of magnetic field strength and the formation of starfish-like equilibrium shapes. We show both numerically and in experiments that the magnetic droplet behaviour may be described with a triaxial ellipsoid approximation. Directions for further research are mentioned, including the dipolar interaction contribution to the surface tension of the magnetic droplets, accounting for the large viscosity contrast between the magnetic droplet and the surrounding fluid.

A generalized multibody model for inversion of magnetic anomalies

Geophysics ◽  
1980 ◽  
Vol 45 (2) ◽  
pp. 255-270 ◽  
Author(s):  
B. K. Bhattacharyya
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Magnetization Vector ◽  
Critical Dimension ◽  
Magnetic Anomalies ◽  
Field Vector ◽  
Magnetic Survey ◽  
Multibody Model ◽  
Anomalous Field ◽  
Rectangular Block

The height of the observation surface above a magnetized region primarily determines the critical dimension of the smallest inhomogeneity in magnetization that can be resolved from magnetic survey data. When a rectangular block is smaller in size than this critical dimension, it appears homogeneously magnetized in the observed magnetic field. This consideration leads to the selection of a unit rectangular block of suitable dimensions with homogeneous magnetization. The magnetized region creating the anomalous field values in the area of observation can, therefore, be broken up into several blocks having different magnetizations, each block being equal in size and uniformly magnetized. The iterative method described here assumes initially that the anomalous field values are caused by a three‐dimensional (3-D) distribution of magnetized rectangular blocks. The optimum orientation of these blocks with respect to geographic north is then determined. This orientation is particularly insensitive to adjustments in the dimensions of the blocks. The top and bottom surfaces of each of the blocks in one or more layers are adjusted in a least‐squares sense to minimize the difference between observed and calculated field values. A method is also described for constraining the magnetization vector of each block to lie within a specified angle of the normal or reversed direction of the geomagnetic field vector. The procedure for analysis of data can also be extended to the case of anomalies over a draped surface. At the conclusion of the iterations, a 3-D distribution of magnetization is generated to delineate the magnetized region responsible for the observed anomalous magnetic field. Examples including model and aeromagnetic data are provided to demonstrate the usefulness of a generalized multibody model for inversion of magnetic anomalies.

Magnetic Circuit Simulation for Magnetorheological (MR) Fluids Testing Rig in Squeeze Mode

2010 ◽  
Vol 123-125 ◽  
pp. 991-994 ◽  
Author(s):  
Izwan Ismail ◽  
Saiful Amri Mazlan ◽  
Abdul Ghani Olabi
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Field Distribution ◽  
Circuit Simulation ◽  
Magnetic Field Distribution ◽  
Mr Fluid ◽  
Flux Lines ◽  
Mr Fluids ◽  
Magnetic Flux Lines ◽  
The Magnetic Field

In this study, a testing rig in squeeze was designed and developed with the ability to conduct various tests especially for quasi-static squeezing at different values of magnetic field strength. Finite Element Method Magnetics (FEMM) was utilized to simulate the magnetic field distribution and magnetic flux lines generation from electromagnetic coil to the testing rig. Tests were conducted with two types of MR fluid. MRF-132DG was used to obtain the behaviour of MR fluid, while synthesized epoxy-based MR fluid was used for investigating the magnetic field distribution with regards to particle chains arrangement. Simulation results of the rig design showed that the magnetic flux density was well distributed across the tested materials. Magnetic flux lines were aligned with force direction to perform squeeze tests. Preliminary experimental results showed that stress-strain pattern of MR fluids were in agreement with previous results. The epoxy-based MR samples produced excellent metallographic samples for carbonyl iron particles distributions and particle chain structures investigation.

Finite Element Modeling and Analysis of Magnetorheological Dampers

2011 ◽  
Author(s):  
David Case ◽  
Behzad Taheri ◽  
Edmond Richer
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Flux ◽  
Weight Ratio ◽  
Magnetorheological Damper ◽  
Plastic Behavior ◽  
Magnetorheological Dampers ◽  
Flux Lines ◽  
Finite Element Software ◽  
Magnetic Flux Lines

A magnetorheological fluid consists of a suspension of microscopic magnetizable particles in a non-magnetic carrier medium. In the absence of a magnetic field, the fluid behaves in a roughly Newtonian manner. When a magnetic field is produced in the same space, the microscopic particles suspended in the fluid become oriented and form chains along the magnetic flux lines, changing the fluid’s rheology. The orientation of these particle chains is crucial to producing the Bingham plastic behavior necessary for high strength-to-weight ratio magnetorheological dampers and actuators. This project uses COMSOL Multiphysics finite element software to examine the magnetic flux lines, field intensity, and non-Newtonian fluid flow within a magnetorheological damper. Several established and novel damper configurations are examined and modified to improve performance while minimizing power draw of the electromagnet.

AXISYMMETRIC RESISTIVE INSTABILITIES IN THE HARD-CORE PINCH

1966 ◽  
Vol 44 (5) ◽  
pp. 1037-1046 ◽  
Author(s):  
R. J. Hosking ◽  
J. H. Blackwell
Keyword(s):  
Magnetic Field ◽  
Growth Rates ◽  
Hydrogen Plasma ◽  
Practical Importance ◽  
Hard Core ◽  
Finite Conductivity ◽  
Core System ◽  
Flux Lines ◽  
Magnetic Flux Lines ◽  
Plasma Diffusion

The hard-core pinch configuration with azimuthal equilibrium magnetic field only is considered. Provided finite conductivity is included, unstable axisymmetric modes are found. These instabilities are apparently due to nonlocalized plasma diffusion across the magnetic flux lines. On the laboratory scale, the growth rates do not appear to be significant, when the material of the conducting shell is mercury. For a hydrogen plasma shell, however, it appears that the growth rates may be of practical importance. It is found that the ratio of the current in the shell to the hard-core current has a significant effect on the "spectrum" of instabilities. This effect in part accounts for the observed relative stability of the hard-core system when there is no axial equilibrium magnetic field.

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