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This paper aims to understand the magnetohydrodynamics (MHD) mechanism in the molten pool under different modes of magnetic field. The comparison focuses on the Lorenz force excitation and its effect on the melt flow and solidification parameters, intending to obtain practical references for the design of magnetic field-assisted laser directed energy deposition (L-DED) equipment.

A three-dimensional transient multi-physical model, coupled with MHD and thermodynamic, was established. The dimension and microstructure of the molten pool under a 0T magnetic field was used as a benchmark for accuracy verification. The interaction between the melt flow and the Lorenz force is compared under a static magnetic field in the X-, Y- and Z-directions, and also an oscillating and alternating magnetic field.

The numerical results indicate that the chaotic fluctuation of melt flow trends to stable under the magnetostatic field, while a periodically oscillating melt flow could be obtained by applying a nonstatic magnetic field. The Y and Z directional applied magnetostatic field shows the effective damping effect, while the two nonstatic magnetic fields discussed in this paper have almost the same effect on melt flow. Since the heat transfer inside the molten pool is dominated by convection, the application of a magnetic field has a limited effect on the temperature gradient and solidification rate at the solidification interface due to the convection mode of melt flow is still Marangoni convection.

This work provided a deeper understanding of the interaction mechanism between the magnetic field and melt flow inside the molten pool, and provided practical references for magnetic field-assisted L-DED equipment design.

The numerical investigation into the stirring induced by an alternating magnetic field, applied in the axial direction of a closed axisymmetric container of conducting fluid, is presented. The interaction between the azimuthal current and magnetic field results in Lorentz forces in the meridional plane which induce the fluid flow. The magnetic Reynolds number is assumed to be smaller than the frequency magnetic Reynolds number. The electromagnetic equations are thus decoupled from the fluid flow equations. The electromagnetic field is first solved, and the body forces determined from this are introduced into the Navier‐Stokes equations. With the flow field known, the quality of mixing is determined by solving the tracer dispersion equation. The finite element method based on a Galerkin formulation is used for the solution of the equations. Three cases are examined: a finite length cylinder, a finite length cylinder with rounded corners and a sphere. In general, two vortices are formed, the equatorial vortex closest to the equator and the end vortex at the closed end. Results show that the introduction of the rounded corner increases the size and strength of the end vortex with the opposite effect on the equatorial vortex. Of the three frequency magnetic Reynolds numbers considered (Rw=30, 100 and 800), Rw=100 results in the best mixing for all cases. Rounding the corner of the cylinder only results in a definite improvement of mixing at Rw=800. The sphere results in even better mixing than this at Rw=800, but is worse than the first two geometries for Rw=30 and 100 when the interaction parameter is large.

The purpose of this paper is to present the vector magnetic properties of the electrical steel sheet and investigate its influences on the magnetic field and iron loss distributions for the electrical machines.

The vector magnetic property of the electrical steel sheet is measured by using a two-dimensional single sheet tester and modelled through an E&S vector hysteresis model to be applied to finite element analysis.

The magnetic field and iron loss distributions are calculated by finite element analysis combined with the E&S vector hysteresis model for the three-phase transformer and induction motor models.

The influences of the vector magnetic property on the electrical machines are verified by comparing with the numerical results from a scalar magnetic property.

The paper describes numerical simulation tools for electromagnetic (EM), hydrodynamic, temperature and concentration fields in industrial Czochralski (CZ) and floating zone (FZ) single silicon crystal growth facilities under the influence of several alternating current (AC) and static DC magnetic fields. Such fields are expected to provide additional means to influence the melt behaviour, especially in the industrial growth of large diameter (200–300 mm) silicon crystals. The simulation tools are based on axisymmetric 2D models for (1) AC and DC magnetic fields in the whole crystal growth facility and (2) hydrodynamics, temperature and mass transport in the melt under the influence of the EM fields. The simulation tools are verified by comparison to temperature and velocity measurements in a laboratory CZ set‐up with eutectics InGaSn model melt and to resistivity measurements in grown silicon crystals.

Introduces the fourth and final chapter of the ISEF 1999 Proceedings by stating electric and magnetic fields are influenced, in a reciprocal way, by thermal and mechanical fields. Looks at the coupling of fields in a device or a system as a prescribed effect. Points out that there are 12 contributions included ‐ covering magnetic levitation or induction heating, superconducting devices and possible effects to the human body due to electric impressed fields.

This paper aims to study the properties of cyclically treated pure water in magnetic fields and its comparison with pure untreated water.

The magnetic treatment was carried out using a static permanent magnetic field and alternating electromagnetic field. We have measured the magnetic effect on the rising level of the water in capillary tubes and the relaxation time for restoration after removing the magnetic field. The dependence on the magnetic field intensity and on the cyclical time treatments was investigated and discussed. The results of magnetization by static field and electromagnetic field were compared and discussed. It is well known that the clustering structure of hydrogen-bonded chains and polarization effects of water molecules are enhanced after magnetization. Therefore, each experimental series was followed by a “memory” test, the results of which enabled us to have some insights into the molecular and hydrogen bonds of water.

It was found that water remembers and keeps the impact of its passing through a magnetic field for several hours and also that many mechanical features were changed under cyclical treatment of a magnetic field.

The purpose of this paper is to continue studies previously reported with the primary focus of optimizing an inductor design. The potential benefits of hyperthermia for cancer therapy, particularly metastatic cancers of the prostate, may be realized by the use of targeted magnetic nanoparticles that are heated by alternating magnetic fields (AMFs).

To further explore the potential of this technology, a high‐throughput cell culture treatment system is needed. The AMF requirements for this research present challenges to the design and manufacture of an induction system because a high flux density field at high frequency must be created in a relatively large volume. Additional challenges are presented by the requirement that the inductor must maintain an operating temperature between 35 and 39°C with continuous duty operation for 1 h or longer. Results of simulation and design of two devices for culture samples and for in vitro tests of multiple samples in uniform field are described.

The inductor design chosen provides a uniform distribution of relatively high magnetic field strength while providing an optimal reduction in the voltage and power requirement. Through development of design and selection of magnetic concentrator, the exposure of the cell cultures to the heat generated by the inductor is minimized.

This method of generating uniform high AC magnetic fields in a large volume is beneficial for the study of hyperthermia in cells for a high throughput, necessary for cancer treatment research.

Describes the design and operating principles of fluxgate sensors and magnetometers. Polarity determination and compensation for temperature and high frequency (> 100Hz) alternating magnetic fields are also discussed.

Three‐phase inductors with a magnetic travelling field are often used to pump a liquid metal or to stir it in induction stirrers. Due to a finite length of inductor an alternating magnetic field is generated as an additional component to the magnetic travelling field. When an induction pump is used with a rectangular shaped transport channel and a flat inductor shown in Fig.1,this component deforms a force distribution in liquid metal and causes some local whirls. This may play a positive role in stirring of molten metal but it cannot be tolerated in the channel of an induction pump,where a smooth flow is required. In that case the alternating magnetic field should be eliminated. It can be done by using an additional compensating winding or by applying a special type of three‐phase winding that eliminates or reduces the alternating field component. The objective of this paper is to examine the magnetic field and force distribution in molten metal of an induction pump when the alternating magnetic field component is compensated.

Detecting the orientation of cracks is a major challenge in the development of eddy current nondestructive testing probes. Eddy current-based techniques are limited in their ability to detect cracks that are not perpendicular to induced current flows. This study aims to investigate the application of the rotating electromagnetic field method to detect arbitrary orientation defects in conductive nonferrous parts. This method significantly improves the detection of cracks of any orientation.

A new rotating uniform eddy current (RUEC) probe is presented. Two exciting pairs consisting of similar square-shaped coils are arranged orthogonally at the same lifting point, thus avoiding further adjustment of the excitation system to generate a rotating electromagnetic field, eliminating any need for mechanical rotation and focusing this field with high density. A circular detection coil serving as a receiver is mounted in the middle of the excitation system.

A simulation model of the rotating electromagnetic field system is performed to determine the rules and characteristics of the electromagnetic signal distribution in the defect area. Referring to the experimental results aimed to detect artificial cracks at arbitrary angles in underwater structures using the rotating alternating current field measurement (RACFM) system in Li et al. (2016), the model proposed in this paper is validated.

CEDRAT FLUX 3D simulation results showed that the proposed probe can detect cracks with any orientation, maintaining the same sensitivity, which demonstrates its effectiveness. Furthermore, the proposed RUEC probe, associated with the exploitation procedure, allows us to provide a full characterization of the crack, namely, its length, depth and orientation in a one-pass scan, by analyzing the magnetic induction signal.