Simulation Of Magnetic Field Distribution Research Articles

Design and analysis of combined standard ferrofluid and centrifugal seals

PurposeFerrofluid seals are known for their low friction torque and high tightness. However, they have some limitation due to the allowable rotational speed. The work presented here analyzes the performance of newly designed seals which are a combination of a ferrofluid and a centrifugal seal. The new seals can operate at high speeds. The purpose of this study is to theoretically predict the performance of combined seals.Design/methodology/approachThree seals were designed and selected for analysis. A version of the seals with a nonmagnetic insert is also considered, the purpose of which is to facilitate the installation and return of ferrofluid during low rotational speeds. The analyses were based on combining the results of numerical simulation of magnetic field distribution with mathematical models.FindingsA combination of ferrofluid sealing and centrifugal sealing is possible. Analyses showed that the combined seal could hold a minimum pressure of 190 kPa in the velocity range of 0–100 m/s. The problem with this type of seal is the temperature.Originality/valueNew seal designs are presented. Key parameters that affect the seal operation are discussed. A methodology that can be used in the design of such seals is presented.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2023-0221/.

Experimental Investigation on the Effect of Surface Shape and Orientation in Magnetic Field Assisted Mass Polishing.

Magnetic field assisted finishing (MFAF) technology has been widely used in industries such as aerospace, biomedical, and the optical field for both external and internal surface finishing due to its high conformability to complex surfaces and nanometric surface finishing. However, most of the MFAF methods only allow polishing piece-by-piece, leading to high post-processing costs and long processing times with the increasing demand for high precision products. Hence, a magnetic field-assisted mass polishing (MAMP) method was recently proposed, and an experimental investigation on the effect of surface posture is presented in this paper. Two groups of experiments were conducted with different workpiece shapes, including the square bar and roller bar, to examine the effect of surface orientation and polishing performance on different regions. A simulation of magnetic field distribution and computational fluid dynamics was also performed to support the results. Experimental results show that areas near the chamber wall experience better polishing performance, and the surface parallel or inclined to polishing direction generally allows better shearing and thus higher polishing efficiency. Both types of workpieces show notable polishing performance where an 80% surface roughness improvement was achieved after 20-min of rough polishing and 20-min of fine polishing reaching approximately 20 nm.

FDTD Simulation of Magnetic Field Distribution in Normal and Blood Cancer for Treatment

Non-invasive cancer treatment has the potential to eliminate infection and scar formation associated with surgery to minimize side effects. Light stimulation can use for treatment to increase efficiency, reduce treatment costs, eliminate infection, etc. Magnetic fields can improve blood circulation in tissues and stimulate the body’s metabolism. The magnetic field can induce joule heating and expand the blood vessels of cancerous tumors. These blood vessels increase the possibility of excess oxygen to enter the tumor creating obstacles to the survival of oxygen-rich cancers. In this study, we investigate finite difference times domain (FTDT) simulation of magnetic field in normal and blood cancer. The low frequency with range 10-106 is used in this study. The maximum magnetic field for normal blood and CLL1 is 400 nm and 250 nm in 125 cm electrode size. While for 50 nm electrode size, the maximum magnetic field in normal blood and CLL 1 is 400 nm and 300 nm. But there The maximum magnetic field for normal blood and CLL1 is 400 nm and 250 nm in 125 cm electrode size. While for 50 nm electrode size, the maximum magnetic field in normal blood and CLL 1 is 400 nm and 300 nm. But there is no peak for blood cancer in final stage CLL2.

Magnetic field distribution simulation and performance experiment of a magnetic seed-metering device based on the combined magnetic system

The magnetic seed-metering method is one of the universal approaches for plug tray seeding. Conventional electromagnetic and permanent-magnetic seed-metering devices either cannot supply a desirable magnitude of magnetic force or need a seed-clearing mechanism. Thus the objective of this research was to develop a combined magnetic system (CMS) seed-metering device for generating higher magnetic forces than the electromagnetic ones without using any auxiliary seed-clearing mechanisms. Firstly, the CMS component was designed and its magnetic field distributions in both attractive and clearing states were obtained by finite element method simulations. Secondly, based on the CMS components, a magnetic seed-metering device was developed and validated by a prototype experiment. The simulation results displayed that along the axial direction of the magnetic head, the maximum magnetic flux density in the clearing state was 21.03% of that in the attractive state. In addition, along the radial direction, the proportion was 24.16%. Concerning the spatial magnetic flux density distribution, the magnetic flux density on the seeding planes of CMS components (approximately 60 mT) was higher than that of transitional space between two CMS components (nearly 0 mT). As for the seeding performance experiment, when the rotational speed of the roller was 21 r/min and the exciting current was 0.15 A, the highest single rate was acquired (90.20%). In the same condition, the reseeding rate was 5.88% and the miss-seeding rate was 3.92%. The results suggest that the magnetic field distribution and seeding performance of the developed magnetic seed-metering device are acceptable. Therefore, the developed magnetic seed-metering device can be used in practical plug tray seeding processes. Keywords: seed-metering device, magnetic field, magnetic flux density, finite element method, simulation DOI: 10.25165/j.ijabe.20211401.5852 Citation: Liu W, Hu J P, Yao M J, Zhao J, Lakhiar I A, Lu C T, et al. Magnetic field distribution simulation and performance experiment of a magnetic seed-metering device based on the combined magnetic system. Int J Agric & Biol Eng, 2021; 14(1): 108–117.

Magnetic field distribution simulation and performance experiment of a magnetic seed-metering device based on the combined magnetic system

The magnetic seed-metering method is one of the universal approaches for plug tray seeding. Conventional electromagnetic and permanent-magnetic seed-metering devices either cannot supply a desirable magnitude of magnetic force or need a seed-clearing mechanism. Thus the objective of this research was to develop a combined magnetic system (CMS) seed-metering device for generating higher magnetic forces than the electromagnetic ones without using any auxiliary seed-clearing mechanisms. Firstly, the CMS component was designed and its magnetic field distributions in both attractive and clearing states were obtained by finite element method simulations. Secondly, based on the CMS components, a magnetic seed-metering device was developed and validated by a prototype experiment. The simulation results displayed that along the axial direction of the magnetic head, the maximum magnetic flux density in the clearing state was 21.03% of that in the attractive state. In addition, along the radial direction, the proportion was 24.16%. Concerning the spatial magnetic flux density distribution, the magnetic flux density on the seeding planes of CMS components (approximately 60 mT) was higher than that of transitional space between two CMS components (nearly 0 mT). As for the seeding performance experiment, when the rotational speed of the roller was 21 r/min and the exciting current was 0.15 A, the highest single rate was acquired (90.20%). In the same condition, the reseeding rate was 5.88% and the miss-seeding rate was 3.92%. The results suggest that the magnetic field distribution and seeding performance of the developed magnetic seed-metering device are acceptable. Therefore, the developed magnetic seed-metering device can be used in practical plug tray seeding processes. Keywords: seed-metering device, magnetic field, magnetic flux density, finite element method, simulation DOI: 10.25165/j.ijabe.20211401.5852 Citation: Liu W, Hu J P, Yao M J, Zhao J, Lakhiar I A, Lu C T, et al. Magnetic field distribution simulation and performance experiment of a magnetic seed-metering device based on the combined magnetic system. Int J Agric & Biol Eng, 2021; 14(1): 108–117.

Analysis of Wireless Power Transfer Using Superconducting Metamaterials

A spiral superconducting metamaterial with an effective negative permeability is presented for efficient wireless power transfer (WPT) using magnetic resonant coupling. The S-parameters of superconducting metamaterials unit cell with respect to different resonance frequencies are obtained by the finite element simulation. The effective permeability of the unit cell of superconducting metamaterials is derived by the S-parameter method, and an analysis of the resonant modes is performed by full-wave simulation. The 3 × 3 planar superconducting metamaterials slab is designed by the proposed unit cell to verify their effects in a WPT system. The effects of superconducting on efficiency enhancement are analyzed by both S-parameter and magnetic field distribution simulation. The optimal position of the superconducting metamaterials is acquired by analyzing the transfer efficiency. We show with simulation results that the transfer efficiency of the system can be improved significantly by the superconducting metamaterials through enhanced evanescent wave coupling and with the lower loss properties of the superconductor.

Design of magnetic Circuit Simulation for Curing Device of Anisotropic MRE

The strength of magnetic field during fabrication of magnetorheological elastomer (MRE) plays a crucial role in order to form a pre-structured MRE. So far, gaussmeter were used to determine the magnetic intensity subjected to the MRE during curing. However, the magnetic flux reading through that measurement considered less accurate. Therefore, a simulation should be done to figure out the magnetic flux concentration around the sample. This paper investigates the simulation of magnetic field distribution in a curing device used during curing stage of anisotropic magnetorheological elastomer (MRE). The target in designing the magnetic circuit is to ensure a sufficient and uniform magnetic field to all the MRE surfaces during the curing process. The magnetic circuit design for the curing device was performed using Finite Element Method Magnetic (FEMM) to examine the magnetic flux density distribution in the device. The material selection was first done instantaneously during a magnetic simulation process. Then, the experimental validation of simulation was performed by measuring and comparing the actual flux generated within the specimen type and the one from the FEMM simulation. İt apparent that the data from FEMM simulation shows an agreement with the actual measurement. Furthermore, the FEMM results showed that the magnetic design is able to provide sufficient and uniform magnetic field all over the surfaces of the MRE.

A novel approach for estimating the magnetization curve of magnetic fluids

PurposeMagnetization is one of the most important parameters of magnetic fluids. The shape of the magnetization curve often determines the application of a fluid in a device. On the basis of the magnetization curve, it is also possible to estimate, for example, the distribution and size of the particles in a magnetic fluid carrier fluid. The aim of this paper is to present a new approach for estimating the magnetization curve.Design/methodology/approachThe proposed method is an iterative method based on the measurement of magnetic induction on a test stand. To determine the magnetization curve, a numerical simulation of the magnetic field distributions for the preliminary magnetization curve should also be performed. Numerical simulations for modified forms of the magnetization curve are performed until the difference between the results obtained by the measurement and numerical simulation are the smallest.FindingsThis paper presents the results of magnetization curve research for ferrofluids and magnetorheological fluids.Originality/valueThe discussed method shows the possibilities of using numerical simulations of magnetic field distribution to determine the magnetic properties of magnetic fluids. This method may be an alternative for estimating the magnetization curve of the magnetic fluid compared to other methods.

Characteristics of Critical Current of HTS Conductor on Round Core

The bend and transposition of high-temperature superconductors (HTS) have great influence on the characteristics of critical current. For Conductor on Round Core (CORC), twist pitch and diameter will influence the characteristics of critical current. The influence of twist pitch and diameter on the critical current characteristics of CORC was studied. In this paper, the simulation of magnetic field distribution of the conductor using FEM was accomplished, and the critical current of the conductor was calculated and discussed in different twist pitch and diameter. Then, the sample of HTS CORC was fabricated, and the critical current was measured at liquid nitrogen temperature and self-field. The test results correspond with simulation.

Axial Magnetic Field Distribution Simulation and Optimization in Rotating Magnetron Sputtering System

The primary goal of this study is to optimize the dynamic axial magnetic field distribution in magnetron sputtering system, guiding the target ions to project directly to the substrate. A group of electromagnetic coils were set up to generate an auxiliary axial magnetic field. The configuration of axial magnetic field in different electrifying modes on coils were simulated using numerical integration. Based on the general theoretical results, this paper proposed an optimization of coil arrangement and electrifying modes for a C-shape direct current(DC) magnetron. A 3D model of the coils was set up and the finite element analysis results verified the accuracy of theoretical results. Consequently, this study proposed an arrangement and electrified scheme of electromagnetic coils to provide a dynamic auxiliary axial magnetic field, which could match with the shape and movement of the primary magnetron.

Experimental and numerical determination of the static critical pressure in ferrofluid seals

Ferrofluids have various engineering applications; one of them are magnetic fluid seals for rotating shafts. There are various constructions of this type of seals, but the main difference is the number of sealing stages. The development of this construction is a complex process which requires knowledge of ferrofluid physical and rheological properties and the magnetic field distribution inside the sealing gap. One of the most important parameters of ferrofluid seals is the critical (burst) pressure. It is the pressure value at which a leak will occur. This study presents results of numerical simulation of magnetic field distribution inside the seal gap and calculations of the critical pressure value. The obtained pressure values were verified by experiments.

Field Determination and Calculation of Stiffness Parameters in an Active Magnetic Bearing (AMB)

Field analysis was applied to the simulation of magnetic field distribution and calculation of its integral parameters in an active magnetic bearing (AMB). 3D Finite Element Method (FEM) was employed for the computations. The magnetic force which act on the moving shift and stiffness parameters of AMB were calculated under the steady state conditions. The measurement results confirm rightness of the field modeling. The inductances of the stator winding coils were computed, as well. They have been used for the analysis of the AMB dynamics, which is not presented here.

3D Simulation of magnetic field distribution in electromagnetic forming systems with field-shaper

Impulse electromagnetic forming (IEMF) is an effective and powerful technique widely used for joining and shaping metals and field-shaper is a main part of the electromagnetic forming which has important effect on the distribution of magnetic field. In this technique, a metal work-piece is pushed to a die and formed by a pressure created using an intensive, transient magnetic field. This magnetic field is produced by passing a pulse of electric current through a forming coil in a pulsed power circuit. The produced transient magnetic field induces eddy currents in the surface of work-piece. Induced eddy currents in work-piece produce a magnetic field with reverse direction of initial magnetic field; this results in a mutual repulsion between coil and work-piece and in this way the work-piece is thrown toward the die. In this process created magnetic forces applied to work-piece are much like uniform, but in real applications, some regions of a work-piece have to be more deformed and therefore a much greater pressure has to be applied to these regions. The task of concentration of magnetic forces to some desired regions can be accomplished using field-shapers. Yu et al. [Yu, H., Li, C., Zhao, Z., Li, Z., 2005. Effects of field-shaper on magnetic pressure in electromagnetic forming. J. Mater. Process. Technol. 168, 245–249] have recently shown the effect of field-shaper on the distribution of the magnetic fields in electromagnetic forming, but because of the nature of 2D simulations some edge effects in real geometries could not be taken into consideration. In this paper, a 3D simulation using the FEA software MAXWELL has been applied to study the magnetic field distribution during an impulse electromagnetic forming process. Comparison of the 3D and 2D simulation results indicates that the maximum magnetic fields achieved in front of nodules of the field-shaper are about 15% stronger than those expected by 2D simulations. By changing the geometry of the field-shaper, the influence of the shape of the field-shaper on the distribution of the applied forces on the work-piece has been studied. Based on these simulations, some simple guidelines to design the field-shaper have been derived.

Numerical Simulation of Magnetic Field Distribution in MAF

Magnetic field distribution (MFD) plays an important role in magnetic abrasive finishing (MAF). The mathematical models of the MFD in MAF have been established, and forced behavior of magnetic abrasive (MA) in the magnetic field has been analyzed in this paper. The MFD characteristics of the grooved poles have been numerically simulated, and the distribution law of magnetic force, interaction force and interface pressure have been investigated based on a single particle. The calculated results show that the MFD in the finishing zone is directly affected by the pole structure and working gap. The mapping function of interaction force and interface pressure corresponds to corner-effect in the peak point of the pole, and the magnetic brush stiffness is changed by the diameter and magnetization characteristics of MA, and the magnetic flux intensity (MFI). The numerical simulations are in a good agreement with the experiments. All of results mentioned above will offer an important method to study further on the finishing mechanism.