scholarly journals Meniscus of a Magnetic Fluid in the Field of a Current-Carrying Wire: Three-Dimensional Numerical Simulations

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 775
Author(s):  
Paul-Benjamin Eißman ◽  
Stefan Odenbach ◽  
Adrian Lange
Keyword(s):  
Magnetic Field ◽  
Magnetic Fluid ◽  
Material Properties ◽  
Three Dimensional ◽  
Applied Current ◽  
Great Strength ◽  
Magnetisation Curve ◽  
The Wire ◽  
The Magnetic Field ◽  
A Current

Three-dimensional calculations of the meniscus of a magnetic fluid placed around a current carrying vertical and cylindrical wire are presented. Based on the material properties of experimentally used magnetic fluids, the numerically determined menisci are compared with the experimentally measured ones reported by May. The comparison is made for a linear law of magnetisation as well as for the experimentally measured nonlinear magnetisation curve. Up to moderate strengths of the applied current ( I < = 45 A), i.e., up to moderate strengths of the magnetic field close to the wire, the calculated profiles agree satisfyingly with the experimentally measured ones for a linear as well as for a nonlinear law of magnetisation. At a great strength of the applied current ( I = 70 A), i.e., at a large strength of the magnetic field close to the wire, the agreement is less good than in the range up to moderate strengths. Our analysis revealed that the numerically assumed isothermal conditions are not present in the experiment, particularly at the great strength of the applied current. A control of the temperature in the experiment and the implementation of a coupled thermal model in the numerics are considered the most relevant future steps for an improved agreement.

scholarly journals Magnetic fluid bridge between two cones and a cylinder in the magnetic field of a current-carrying wire

2018 ◽  
Vol 185 ◽  
pp. 09010
Author(s):  
Alexandra S. Vinogradova ◽  
Vladimir A. Turkov ◽  
Vera A. Naletova
Keyword(s):  
Magnetic Field ◽  
Pressure Drop ◽  
Numerical Modelling ◽  
Magnetic Fluid ◽  
Surface Shape ◽  
Zero Current ◽  
The Wire ◽  
The Magnetic Field ◽  
A Current ◽  
Hysteresis Phenomena

A magnetic fluid (MF) changes its surface shape in the magnetic field of a current-carrying wire while the current is changing. In the present paper, we propose to study a MF bridge which can open or close the channel formed by two cones and a cylinder by imposing the magnetic field of a wire. Numerical modelling of the bridge behavior for different values of MF volumes and currents in the wire is done for two cases: when the MF wets and does not wet surrounding solid boundaries. It is shown that the presence of limiting cones allows the MF to sustain the pressure drop which is much higher in case of non-wetting than in case of wetting. In case of wetting, the MF cannot sustain any pressure drop at low currents, but in case of non-wetting, the MF can do it even at zero current. It is found that in case of non-wetting, spasmodic and hysteresis phenomena are possible for some values of MF volumes and currents in the wire. The use of a MF in valves, dispensers and pumps is one of possible actuation methods.

scholarly journals Three-Dimensional Magnetic Fluid Boundary Layer Flow Over a Linearly Stretching Sheet

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
E. E. Tzirtzilakis ◽  
N. G. Kafoussias
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Magnetic Fluid ◽  
Boundary Layer Flow ◽  
Stretching Sheet ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Magnetic Interaction ◽  
Layer Flow ◽  
The Magnetic Field

The three-dimensional laminar and steady boundary layer flow of an electrically nonconducting and incompressible magnetic fluid, with low Curie temperature and moderate saturation magnetization, over an elastic stretching sheet, is numerically studied. The fluid is subject to the magnetic field generated by an infinitely long, straight wire, carrying an electric current. The magnetic fluid far from the surface is at rest and at temperature greater of that of the sheet. It is also assumed that the magnetization of the fluid varies with the magnetic field strength H and the temperature T. The numerical solution of the coupled and nonlinear system of ordinary differential equations, resulting after the introduction of appropriate nondimensional variables, with its boundary conditions, describing the problem under consideration, is obtained by an efficient numerical technique based on the common finite difference method. Numerical calculations are carried out for the case of a representative water-based magnetic fluid and for specific values of the dimensionless parameters entering into the problem, and the obtained results are presented graphically for these values of the parameters. The analysis of these results showed that there is an interaction between the motions of the fluid, which are induced by the stretching surface and by the action of the magnetic field, and the flow field is noticeably affected by the variations in the magnetic interaction parameter β. The important results of the present analysis are summarized in Sec. 6.

Construction of a Cost Effective Current Balance for Physics Teaching

2013 ◽  
Vol 770 ◽  
pp. 374-377
Author(s):  
Apichart Sankote ◽  
Kheamrutai Thamaphat ◽  
Supanee Limsuwan
Keyword(s):  
Magnetic Field ◽  
Uniform Magnetic Field ◽  
Magnetic Force ◽  
Magnetic Field Direction ◽  
Horizontal Segment ◽  
Applied Current ◽  
Copper Sheet ◽  
Physics Teaching ◽  
The Magnetic Field ◽  
A Current

In this work, a method to measuring the magnitude of a uniform magnetic field in space using current balance was described. A simple experimental set was designed and constructed using low-cost materials. This constructed current balance consists of copper sheet, weight pan, and acrylic sheet. A copper sheet was cut into a U-shape and attached at the end of acrylic balance arm. A weight pan was hanged in the opposite side of the balance arm with high sensitivity to a small torque. The horizontal segment of the U-shaped copper sheet, which the length l was 3 cm, was located inside the influence of an uniform magnetic field produced by two parallel bar magnets with opposite poles facing each other. The magnetic field direction was perpendicular to the horizontal segment. When a current was supplied to the copper sheet, the magnetic force acting on a horizontal segment of length l carrying a current I in a magnetic field B was given by. In the experiment, the current was varied from 0 1 A. For each value of applied current, the magnetic force on a thin straight sheet of length l was measured by adding masses to the pan until the balance arm moved to the equilibrium between opposing gravitational and magnetic forces. The results showed that the magnetic force increased linearly with increasing applied current. By plotting a linear graph of magnetic force versus applied current, the magnetic field B can be calculated from . The calculated and actual values of B were 100.32 and 100.13 mT, respectively. This constructed current balance is an excellent tool for high school and undergraduate fundamental physics courses. Students will be excited when they see the balance arm rising or going down due to magnitude and direction of current flowing in a conductor wire.

Resistive MHD stagnation-point flows at a current sheet

1975 ◽  
Vol 14 (2) ◽  
pp. 283-294 ◽  
Author(s):  
B. U. Ö. Sonnerup ◽  
E. R. Priest
Keyword(s):  
Magnetic Field ◽  
Current Sheet ◽  
Stagnation Point ◽  
Three Dimensional ◽  
Mhd Equations ◽  
Viscous Effects ◽  
Three Dimensional Flow ◽  
Merging Process ◽  
The Magnetic Field ◽  
A Current

A family of exact solutions to the MHD equations is presented for steady incompressible two- and three-dimensional flow in the vicinity of the stagnation point, which forms in a current sheet separating two colliding plasma streams. The magnetic field in each plasma is strictly parallel to the current sheet, but can have different magnitudes and directions. Resistive and viscous effects are accounted for. These flows are of considerable interest in connexion with the magnetic field merging process. They represent the limit of resistive field annihilation with zero reconnexion.

scholarly journals The galvanometer constant of a circular coil of many windings

1935 ◽  
Vol 150 (871) ◽  
pp. 487-494
Keyword(s):  
Magnetic Field ◽  
Rectangular Channel ◽  
Number Of Layers ◽  
Circular Coil ◽  
Absolute Measure ◽  
The Mean ◽  
The Wire ◽  
The Magnetic Field ◽  
A Current

In a number of investigations the strength of the magnetic field at the centre of a circular coil of many turns due to a current in the coil is required. Among these may be mentioned the determination of the ampere in absolute measure by the method adopted by Rayleigh and Sidgwick. Let a be the mean radius of the coil, N the number of turns, 2 b and 2 c the axial and radial dimensions of the rectangular channel in which the coil is wound, d and d 0 the covered, α bare diameters of the wire, m the number of windings in a layer, and n the number of layers.

scholarly journals Analysis of Injected Electron Beam Propagation in a Planar Crossed-Field Gap

2021 ◽  
Vol 11 (6) ◽  
pp. 2540
Author(s):  
Ranajoy Bhattacharya ◽  
Adam M. Darr ◽  
Allen L. Garner ◽  
Jim Browning
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Three Dimensional ◽  
One Dimensional ◽  
Field Device ◽  
The Magnetic Field ◽  
A Current

This paper examines basic crossed-field device physics in a planar configuration, specifically electron beam perturbation and instability as a function of variation in magnetic field, and angle between magnetic and electric field. We perform a three-dimensional (3-D) simulation of electron perturbation in a planar crossed-field system using the full 3-D particle trajectory solver in CST Particle Studio (CST-PS). The structure has a length, height, width and anode-sole gap of 15 cm, 2 cm, 10 cm, and 2 cm, respectively. The anode to sole voltage is fixed at 3 kV, and the magnetic field and injected current varied from 0.01 T to 0.05 T and 1.5 mA to 1 A, respectively. The simulations show that applying a magnetic field of 0.05 T makes the beam stable for a critical current density of 94 mA/cm2 for an anode-sole gap of 20 mm. Above this current density, the beam was unstable, as predicted. Introducing a 1° tilt in the magnetic field destabilizes the beam at a current density of 23 mA/cm2, which is lower than the critical current density for no tilt, as predicted by our theory. The simulation results also agree well with prior one-dimensional (1-D) theory and simulations that predict stable bands of current density for a 5° tilt where the beam is stable at low current density (<13.3 mA/cm2), unstable above this threshold, and then stable again at higher current density, (>33 mA/cm2).

Study of MFM Application in Semiconductor Failure Analysis

2004 ◽  
Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao
Keyword(s):  
Magnetic Field ◽  
Failure Analysis ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Current Flow ◽  
Force Microscopy ◽  
The Magnetic Field ◽  
A Current

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.

scholarly journals Magnetic Field Structure of Star Forming Regions: VLBI Spectral Line Results

1984 ◽  
Vol 110 ◽  
pp. 333-334
Author(s):  
J.A. Garcia-Barreto ◽  
B. F. Burke ◽  
M. J. Reid ◽  
J. M. Moran ◽  
A. D. Haschick
Keyword(s):  
Magnetic Field ◽  
Three Dimensional ◽  
Aperture Synthesis ◽  
Stokes Parameters ◽  
Hii Region ◽  
Star Forming ◽  
Star Forming Regions ◽  
Vlbi Observations ◽  
The Magnetic Field ◽  
Synthesis Experiment

Magnetic fields play a major role in the general dynamics of astronomical phenomena and particularly in the process of star formation. The magnetic field strength in galactic molecular clouds is of the order of few tens of μG. On a smaller scale, OH masers exhibit fields of the order of mG and these can probably be taken as representative of the magnetic field in the dense regions surrounding protostars. The OH molecule has been shown to emit highly circular and linearly polarized radiation. That it was indeed the action of the magnetic field that would give rise to the highly polarized spectrum of OH has been shown by the VLBI observations of Zeeman pairs of the 1720 and 6035 MHz by Lo et. al. and Moran et. al. VLBI observations of W3 (OH) revealed that the OH emission was coming from numerous discrete locations and that all spots fell within the continuum contours of the compact HII region. The most detailed VLBI aperture synthesis experiment of the 1665 MHz emission from W3 (OH) was carried out by Reid et. al. who found several Zeeman pairs and a characteristic maser clump size of 30 mas. In this work, we report the results of a 5 station VLBI aperture synthesis experiment of the 1665 MHz OH emission from W3 (OH) with full polarization information. We produced VLBI synthesis maps of all Stokes parameters of 16 spectral features that showed elliptical polarization. The magnitude and direction of the magnetic field have been obtained by the detection of 7 Zeeman pairs. The three dimensional orientation of the magnetic field can be obtained, following the theoretical arguments of Goldreich et. al., from the observation of π and σ components.

scholarly journals INCREASING THE EFFICIENCY OF MULTY-VARIANT CALCULATIONS OF ELECTROMAGNETIC FIELD DISTRIBUTION IN MATRIX OF A POLYGRADIENT SEPARATOR

2021 ◽  
Author(s):  
Jasim Mohmed Jasim Jasim ◽  
Iryna Shvedchykova ◽  
Igor Panasiuk ◽  
Julia Romanchenko ◽  
Inna Melkonova
Keyword(s):  
Magnetic Field ◽  
Field Distribution ◽  
Three Dimensional ◽  
Magnetic Potential ◽  
Geometric Parameters ◽  
Two Dimensional ◽  
Air Gaps ◽  
Vector Magnetic Potential ◽  
Electromagnetic Separator ◽  
The Magnetic Field

An approach is proposed to carry out multivariate calculations of the magnetic field distribution in the working gaps of a plate polygradient matrix of an electromagnetic separator, based on a combination of the advantages of two- and three-dimensional computer modeling. Two-dimensional geometric models of computational domains are developed, which differ in the geometric dimensions of the plate matrix elements and working air gaps. To determine the vector magnetic potential at the boundaries of two-dimensional computational domains, a computational 3D experiment is carried out. For this, three variants of the electromagnetic separator are selected, which differ in the size of the working air gaps of the polygradient matrices. For them, three-dimensional computer models are built, the spatial distribution of the magnetic field in the working intervals of the electromagnetic separator matrix and the obtained numerical values of the vector magnetic potential at the boundaries of the computational domains are investigated. The determination of the values of the vector magnetic potential for all other models is carried out by interpolation. The obtained values of the vector magnetic potential are used to set the boundary conditions in a computational 2D experiment. An approach to the choice of a rational version of a lamellar matrix is substantiated, which provides a solution to the problem according to the criterion of the effective area of the working area. Using the method of simple enumeration, a variant of the structure of a polygradient matrix with rational geometric parameters is selected. The productivity of the electromagnetic separator with rational geometric parameters of the matrix increased by 3–5 % with the same efficiency of extraction of ferromagnetic inclusions in comparison with the basic version of the device

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