Influence Of Electromagnetic Force Research Articles

The unexpected role of heliospheric boundaries in facilitating interstellar dust penetration at 1–5 AU

Aims. Interstellar dust (ISD) particles penetrate the heliosphere because of the relative motion of the local interstellar cloud and the Sun. The penetrated particles pass through the heliospheric interface, that is, the region in which solar wind and interstellar plasma interact. As a result, the ISD flow is modified after the passage through this region under the influence of electromagnetic force. The main goal of this work is to show how the heliospheric interface affects the distribution of ISD particles near the Sun. Methods. We have developed a Monte Carlo model of the ISD distribution in the heliosphere. It first takes the effects of the heliospheric interface and the rotating heliospheric current sheet into account. The effects of the heliospheric interface were probed using a global heliospheric model. Results. The computation results show that the heliospheric interface strongly influences the distribution of relatively small (radius a = 150 − 250 nm) astronomical silicates. The unexpected finding is that the heliospheric interface facilitates the penetration of a = 150 nm particles at small heliocentric distances and, particularly, to the Ulysses orbit (1 − 5 AU). We demonstrate that the deflection of ISD particles in the outer heliosheath is the principal mechanism that causes the effects of the heliospheric interface on the distribution near the Sun. The computations with different heliospheric models show that the distribution near the Sun is sensitive to the plasma parameters in the pristine local interstellar medium. Thus, we demonstrated that being measured near the Sun, the ISD may serve as a new independent diagnostics of the local interstellar medium and the heliospheric boundaries.

Dynamics Analysis of a Rolling Rotor Compressor Considering the Electromagnetic Force

Rolling rotor compressor is a commonly used compressor in air conditioning systems, and studying its internal dynamic characteristics plays an important role in the vibration and noise of air conditioning systems. Due to the integration of the motor rotor and shaft inside the compressor, the influence of electromagnetic force needs to be considered when analyzing the dynamics of the compressor. This paper studies the rotor dynamics characteristics of a rolling rotor compressor, considering not only the bearing force and gas force inside the cylinder, but also the electromagnetic force of the motor rotor. Firstly, the gas force, electromagnetic force, and bearing force on the compressor shaft are analyzed; Secondly, a two degree of freedom rotor bearing dynamic model of the compressor shaft is established, and the dynamic characteristics of the shaft are obtained by solving the model though the Runge-Kutta method; Finally, the vibration characteristics of the compressor shaft are analyzed in both the time and frequency domains. The results indicate that the influence of electromagnetic force cannot be ignored, and the coupling effect between electromagnetic force and bearing force can be seen.

Enhancing the bend angle and mechanical properties of mild steel using fiber laser bending technique under the influence of electromagnetic force

The aim of present research work is to develop an electromagnetic-force-assisted laser bending setup and to enhance the laser forming characteristics of mild steel. In present research work, mild steel strips having 2 mm thickness are used for forming operation with the variation of input parameters i.e., laser power (400, 600, 800, 1000 W), beam diameter (2, 4, 6, 8, 10 mm) and scan speed (1000, 1500, 2000, 2500 mm/min). Results indicated that laser bending of mild steel with the electromagnetic attraction significantly enriches the performance parameters i.e., bend angle, micro-hardness and microstructure. Furthermore, it is revealed that the high value of bend angle (20.37 0) is obtained at laser power and scanning speed of 1000 W and 1000 mm/min respectively. In addition, the high micro-hardness (179 HV) and fine grain structure is obtained at laser power of 1000 W and scanning speed of 1000 mm/min. Results of high hardness are mainly attributed due to the fine grain structure and heat absorption at irradiated zone. In addition, beam diameter, air gap and applied current have also a significant effect on laser bending. The laser characteristics significantly improved at beam diameter of 4 mm, air gap of 20 mm and applied current 6 amp during the fiber based electromagnetic force assisted laser bending.

Anisotropic stress softening of electromagnetic Mullins materials

The influence of electromagnetic forces in purely elastic deformable solids has been extensively studied in the literature. However, to the best of the author’s knowledge, the influence of electromagnetic fields on anisotropic Mullins materials has not been studied. In view of this, we propose an anisotropic phenomenological model to describe anisotropic stress softening of electromagnetic Mullins materials; taking note that most materials are not purely elastic and some of them exhibit an anisotropic stress-softening phenomenon widely known as the Mullins effect. The proposed anisotropic model is based on the use of direction-dependent damage parameters and a set of anisotropic spectral invariants, presented recently in the literature by the author. The spectral invariants have a clear physical meaning which is useful in aiding the design of a rigorous experiment to construct a specific form of constitutive equation. Since boundary value results for electromagnetic Mullins materials are not found in the literature, the effect of electromagnetic fields on the Mullins phenomena in simple tension and simple shear deformations is discussed in this paper.

Production of aluminum alloy onboard wire with a high content of rare-earth metals produced using electromagnetic crystallization

The Scientific and Production Center for Magnetic Hydrodynamics Ltd has developed an innovative technology for casting long ingots of small diameter (8–12 mm) into an electromagnetic mold (EMM) and manufacturing thin wire (0.5 mm in diameter) from them for onboard wires from 01417 alloy. Crystallization of liquid metal occurs under the influence of electromagnetic forces in an electromagnetic mold with direct supply of coolant to the ingot, due to which cooling rates are achieved that ensure the dispersion of the eutectic phases of rare earth metal aluminides, similarly to how it takes place during the crystallization of granules (~1.103...1.104 K/s). It has been established that the determining parameters in casting ingots are the power supplied to the inductor and the level of the melt above the crystallization front. For the casting to reach a steady state (the process of stabilizing the diameter of the ingot after the start of casting), it is necessary to regulate the melt level for some time. The surface quality of the ingot depends on ensuring stability of the current in the inductor during casting. Fluctuations in the current in the inductor lead to changes in the ingot`s diameter. Casting speed and metal temperature have a great influence on the structure of ingots. In contrast to the method of producing granulated wire with a thin (less than 1 mm) cross-section, which turned out to be problematic due to numerous breaks during drawing associated with the presence of oxide and foreign inclusions, the casting technology in the electromagnetic mold does not require preliminary metal filtration, since oxide and solid non-metallic inclusions are intensively squeezed out by electromagnetic forces onto the ingot`s surface. It has been established that hot deformation of a billet cast in the EMM at the Conform facility provides higher strength characteristics of the wire from the 01417 alloy after drawing compared to the cast annealed billet. Pressing provided an increase in the yield strength and relative elongation of the 01417 alloy by 2 and 2.5 times, respectively, compared with the cast state. As a result, the billet was obtained with high technological plasticity for further drawing. Electron microscopic studies of the wire have been carried out, which have shown that dispersed REM aluminides are rather uniformly distributed over the cross section of the wire with a diameter of 0.5 mm. Determination of the particle size of aluminides at ×50000 magnification showed that their size is ~96–214 nm. Wire from 01417 alloy is used by JSC “Special Design Bureau of the Cable Industry” (JSC “OKB KP”) for the manufacture of conductive cores of installation wires, providing a significant reduction in their weight.

The Effects of Electrical Conductivity on Fluid Flow between Two Parallel Plates in a Porous Medioum

This paper deals with a mathematical model of a fluid flowing between two parallel plates in a porous medium under the influence of electromagnetic forces (EMF). The continuity, momentum, and energy equations were utilized to describe the flow. These equations were stated in their nondimensional forms and then processed numerically using the method of lines. Dimensionless velocity and temperature profiles were also investigated due to the impacts of assumed parameters in the relevant problem. Moreover, we investigated the effects of Reynolds number , Hartmann number M, magnetic Reynolds number , Prandtl number , Brinkman number , and Bouger number , beside those of new physical quantities (N , ). We solved this system by creating a computer program using MATLAB.

Numerical study on temperature rise and mechanical properties of winding in oil-immersed transformer

In the present paper, the electromagnetic-fluid-thermal-mechanical stress coupling process in an oil-immersed transformer is numerical studied with finite element method. The relationship between electromagnetic force and flux leakage, interaction of losses, temperature and oil flow, and the influence of electromagnetic force and temperature rise on mechanical characteristics of coil are carefully analyzed. Firstly, the leakage flux is mainly generated at the ends of coil and core corner end. The electromagnetic force of B-Phase low voltage coil is the highest due to the leakage flux superimposition caused by A-Phase and C-Phase coils and higher current on B-Phase low voltage coil itself. Secondly, the interaction between losses, temperature and oil flow is remarkable. Compared with the results as heat source is constant, the loss density of high and low voltage coil increased by 18.18% and 14.87%, respectively, and the hot spot temperature increased by 7.06 K. Finally, it is revealed that the coil deformation is mainly caused by thermal load, and little affected by electromagnetic force. The frequency of stress is twice as high as that of energized current. The stress at both ends of the coil is the highest and it would lead to fatigue failures.

Influence of electromagnetic forces in the gaps of a protective CT

Two of the main problems studied in protective current transformers (CTs) are the saturation and residual flux in the ferromagnetic core. To minimise the effects of high saturation levels and residual flux, a gapped core CT can be employed. Although solving both issues, research reports that the introduction of gaps in the ferromagnetic core can develop into a mechanical fragility when compared with a closed core. However, the fragility is not proven in the research. To investigate the mechanical fragility of a gapped core CT, this research aims to verify the influence of the electromagnetic forces in the gap borders of a protective CT under a short-circuit condition. The influence was verified in three different gap lengths: 8, 16 and 24 mm. On the basis of the results, the electromagnetic forces in the gap borders of a protective CT did not influence the CT response.

Воздействие электромагнитных сил на двухфазную среду

Воздействие электромагнитных сил на двухфазную среду

Short-Circuit Strength of Power Transformer Windings-Verification of Tests by a Finite Element Analysis-Based Model

A test stand to evaluate the radial buckling strength of power transformer windings under the influence of electromagnetic forces is presented. The resulting conductor deformation can be measured in parallel to the sinusoidal test current. The proposed test results focus on the inception of forced buckling for continuously transposed conductors (CTCs), which are a special type of conductor often used in power transformer windings. In the literature, there barely exist calculations to the radial buckling withstand capability of CTCs. Therefore, a finite-element analysis-based simulation model for this kind of conductor is proposed and verified by the tests. For this verification, three different CTC types are used. The final simulation model is based on a coupled analysis of magnetostatic force calculation and static structural deformation analysis. It suitably reproduces the measurement results from the dynamic short-circuit tests. Furthermore, a standard formula describing radial buckling phenomena inside power transformers is adapted for use with CTCs.

Modelling of the influence of electromagnetic force on melt convection and dopant distribution at floating zone growth of silicon

Modelling of the influence of electromagnetic force on melt convection and dopant distribution at floating zone growth of silicon

Influence of Electromagnetic Force on Solidification of Cu-Cr-Zr Alloy

In order to improve the distribution of second phase and performance the Cu-Cr-Zr alloy was processed by solidification under the effect of electromagnetic stirring (EMS) and in situ drawing deformation. Study of Cu-Cr-Zr conductivity and mechanical properties under different deformation strains was also carried out, to analyze the effect of EMS on Cu-Cr-Zr alloys. The experimental results showed that the Cr dendrites tended to be smaller and shorter in Cu-10Cr-0.1Zr alloy solidified with EMS (16Hz, 100A). Since electromagnetic stirring have the role to break dendrite,it’s beneficial to increase the amount of dendrites and decrease the size of dendrites. The tensile strength of Cu-10Cr-0.1Zr wire solidified with EMS was higher than that solidified without EMS.

Modelling of the influence of electromagnetic force on melt convection and dopant distribution at floating zone growth of silicon

Modelling of the influence of electromagnetic force on melt convection and dopant distribution at floating zone growth of silicon

Coupled modes in magnetized dense plasma with relativistic-degenerate electrons

Low frequency electrostatic and electromagnetic waves are investigated in ultra-dense quantum magnetoplasma with relativistic-degenerate electron and non-degenerate ion fluids. The dispersion relation is derived for mobile as well as immobile ions by employing hydrodynamic equations for such plasma under the influence of electromagnetic forces and pressure gradient of relativistic-degenerate Fermi gas of electrons. The result shows the coexistence of shear Alfven and ion modes with relativistically modified dispersive properties. The relevance of results to the dense degenerate plasmas of astrophysical origin (for instance, white dwarf stars) is pointed out with brief discussion on ultra-relativistic and non-relativistic limits.

Pulsed Vector Magnetic Potential Field Existence

Experimental confirmation discussed the effect of the immediate surroundings of a pulse-powered toroidal coil on biological material which was placed in an environment without the influence of electromagnetic force.

Modeling and simulation of anode melting pool flow under the action of high-current vacuum arc

In this paper, a transient magnetohydrodynamic (MHD) model of an anode melting pool (AMP) flow (AMPF) is established. Mass equation, momentum equations along axial, radial and azimuthal directions, energy equation, and current continuity equations are considered in the model. In the momentum equations, the influence of electromagnetic force, viscosity force and Marangoni force (anode surface shear stress) are included. Joule heating is also included in the energy equations. According to the MHD model of AMPF, the influence of different heat flux densities to melting pool flow velocities (including azimuthal, radial, and axial velocity), anode temperature, fraction of liquid, melting depth, melting radius, and anode vapor flux will be analyzed. In the AMP, the azimuthal velocity is dominant, whose value approximately approaches velocity magnitude, the radial velocity is much smaller than azimuthal velocity, and the axial velocity is the smallest one compared with radial and azimuthal velocity. According to simulation results, anode surface temperature, melting width, melting depth, and anode vapor flux are increased with the increase in heat flux densities, but the increase in azimuthal velocity is not significant. Simulation results also show that the maximum anode temperature appears near 6.5–7 ms (50 Hz), but the maximum velocity of AMPF appears near 8–10 ms, which is in agreement with the experimental observation. Simulation result of AMPF swirl velocity (about 0.4 m/s) is approximately close to experimental result (about 0.6 m/s) based on high-speed camera data. Simulation results also show that the influence of joule heating and radiation on anode temperature can be neglected. The influence of Marangoni force on AMPF is significant.

Estimation of energy dissipated during superconducting wire motion in a magnetic field

An experiment was carried out to study the motion of superconducting wire under the influence of electromagnetic force. Experiments were conducted at 4.2 K by varying the experimental conditions such as tension to the superconducting wire, current ramp rate, and the use of different insulating materials at the interface of the superconducting wire. We were able to examine in detail the structure of the voltage spikes caused by sudden wire motion. The velocity of the wire motion, distance moved by the wire, and energy dissipated during wire motion are estimated.

THE ACCELERATION OF STATIONARY CHARGED DUST GRAINS BY PROPAGATING COLLISIONLESS SHOCK WAVES

We consider the acceleration of charged particles, which are initially completely at rest with respect to the local upstream plasma rest frame, by collisionless shocks propagating through a static, irregular magnetic field. A relevant example is the interaction of cold, charged interstellar dust grains with a shock associated with a supernova blast wave propagating through the fluctuating interstellar magnetic field. We treat the dust grains as test particles moving under the influence of electromagnetic forces arising from a magnetic field which has an average plus a fluctuating part, and is static in the local plasma frame. The only electric field is that which arises from the flow of plasma across the magnetic field. We find that a significant fraction of the dust grains are accelerated to more than 10 times the shock speed within 100 cyclotron periods. The percentage of those incident on the shock that are accelerated depends strongly on the turbulence variance, but is essentially independent of average shock-normal angle provided the fluctuation amplitude is of the same order as the mean. Our results are relevant to the 'injection problem' in shock acceleration of charged particles.

Experimental setup to detect superconducting wire motion

An experimental setup was designed and fabricated to study superconducting wire motion under the influence of electromagnetic force. Experiments were conducted at 4.2 K by varying the experimental conditions such as the tension to the superconducting wire and different insulating materials at the interface of the superconducting wire and head part. The insulating materials used in the experiments were polyimide film and a high strength polyethylene fiber cloth, Dyneema. Details of the experimental setup and the test results are reported in this paper.

The Influence of Electromagnetic Force Upon the Noise of an IPM Motor Used in a Compressor

Recent power electronics and control technology have equipped air conditioners with additional functions such as air purification and energy saving, however, the noise and vibration originating with the compressor still remains to be improved. The interior permanent magnet (IPM) motor has become the compressor drive motor of choice became of the need for small high-powered compressors. Due to the structural peculiarity of IPM, it generates not only magnetic torque, but also reluctance torque which helps to achieve high power density while aggravating the noise problem. In this study the influences of natural frequencies and mode shapes of the structures were investigated to reduce the noise and vibration of an IPM motor. For better understanding of noise source, electromagnetic force has to be analyzed and this papers deals with noise problem caused only by electromagnetic force