International Journal of Applied Electromagnetics and Mechanics - Volume 59, issue 2

Authors: Vinsard, Gérard | Dufour, Stéphane

Article Type: Research Article

Abstract: A model to compute the forces between small and thin co-planar magnetic disks submitted to an uniform source magnetic field is built with the help of a pseudo magnetic dipole formula, in a similar way as the one used for beads. These forces are used to compute the motion of such disks floating on the top of a viscous liquid. Numerical results are compared to experimental data: it shows a good qualitative accordance.

Keywords: Magnetic dipole, demagnetizing factor, magnetic disk

DOI: 10.3233/JAE-171009

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 385-390, 2019

Authors: Song, Yaqin | Yang, Xiaogang | Dong, Tianbao

Article Type: Research Article

Abstract: The elastic vibration response of coat layered semiconducting microcantilevers, which were excited with a frequency-modulated pump laser and detected with another probe beam, was studied experimentally and theoretically in this paper. The photothermal vibration frequency spectra were measured and analyzed for a set of microcantilevers with different coating thickness at the region near the first resonant frequency. Also the vibrations of microcantilevers were calculated using coupled carrier dispersion, thermal wave and elastic wave equations. The results showed that the experimental results had a good agreement with the theoretical ones.

Keywords: Photothermal, vibration, coating, microcantilevers

DOI: 10.3233/JAE-171093

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 391-397, 2019

Authors: Delannoy, Yves | Martin-Lopez, Elena | Benoit, Fabrice

Article Type: Research Article

Abstract: This paper presents a theoretical study of the radial velocity profile in an annular linear electromagnetic pump, such as the liquid sodium pumps foreseen in some future GenIV nuclear reactors. In contrast with the classical uniform velocity hypothesis, this study makes the hypothesis of a non-uniform profile controlled by an equilibrium between the pressure gradient and the electromagnetic forces. Some typical semi-analytic results are shown, both for quasi-synchronism regimes and for regimes where the slip magnetic Reynolds number is greater than 1.

Keywords: Electromagnetic pump, MagnetoHydroDynamics, sodium

DOI: 10.3233/JAE-171182

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 399-405, 2019

Authors: Wang, Donglai | Lu, Tiebing | Chen, Bo | Li, Xuebao | Xie, Li | Zhao, Luxing | Ju, Yong

Article Type: Research Article

Abstract: The 3D upstream FEM is applied to calculate the ion flow field near the crossing of two circuit ±800 kV UHVDC transmission lines. In order to deal with the interaction of two circuit lines, an improved space charge density correcting treatment on the conductor surfaces is proposed. Compared with the traditional method, the conductor surface electric fields could be closer to the corona onset electric fields by using the improved correction treatment. Then, an experimental platform is established in the laboratory to testify the calculation method. Comparison of the calculated and measured ground-level ion current density proves the validity of calculation …method. Finally, the distribution characteristics of space charge density and electric field strength near the crossing area are analyzed. The crossing structure of bipolar HVDC lines improves the corona discharge level in the opposite polarity crossing area significantly. Show more

Keywords: Corona discharge, ion flow field, HVDC lines, crossing, upstream FEM

DOI: 10.3233/JAE-171145

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 407-415, 2019

Authors: Schellekens, Hans | Wu, You | Wang, Lijun | Qian, Zhonghao | Godechot, Xavier

Article Type: Research Article

Abstract: Contact geometry evaluation using a full 3D Magneto-Hydrodynamic vacuum arc model is presented. The 3D model uses a two-step approach. The time dependent magnetic field is calculated by Flux3D® using the features of the arc control in axial magnetic field (AMF) type vacuum interrupters (VIs). The arc is modeled by a single fluid description of the arc plasma in Fluent®. Current flow is addressed by Ohms law. The model is applied to 3 contact geometries used in commercial AMF VI’s. The general results of the model like ion density, flow fields and energy flow are represented. It is demonstrated that …the external transverse magnetic field created by neighboring phases in a circuit breaker causes off-axis deflection of the heat flow to anode. The deflection in the anti-Amperian direction is attributed to the boundary condition of the current flow at the cathode side. Show more

Keywords: 3-D magnetohydrodynamic (MHD) model, magnetic field (MF), numerical simulation, vacuum arcs

DOI: 10.3233/JAE-171103

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 417-425, 2019

Authors: Wang, Kaiqiang | Xie, Shejuan | Li, Shiyang | Shi, Pengpeng | Tian, Shuxia | Chen, Zhenmao

Article Type: Research Article

Abstract: Electromagnetic force due to induced eddy current during plasma disruptions is one of the key design-driving issues for the first wall (FW) in the Tokamak device. In this paper, a method to evaluate the electromagnetic force in the FW is proposed based on inversion of the measured magnetic field. An inversion scheme for reconstruction of eddy current from measured magnetic field is developed based on a newly proposed algorithm that can eliminate the effect of plasma current. To solve this inverse problem, the conjugate gradient (CG) algorithm is adopted in addition with an efficient parameterization strategy of eddy current distribution. …To demonstrate the efficiency of the method, a simplified FW plate and plasma current model is considered with the magnetic field simulated with a numerical code of the reduced magnetic vector potential (Ar) formulation. The numerical results show that proper eddy current and electromagnetic force distribution can be predicted even for case of unknown plasma current, which reveals that the proposed method has good potential to be applied to the electromagnetic force evaluation of practical Tokamak problem. Show more

Keywords: Electromagnetic force, eddy current reconstruction, first wall, inverse analysis

DOI: 10.3233/JAE-171086

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 427-437, 2019

Authors: Kanki, Takashi | Nagata, Masayoshi

Article Type: Research Article

Abstract: Two-fluid (ions and electrons) flowing equilibrium configurations of spherical torus plasma are numerically determined by using the multi-grid method. The axisymmetric equilibrium equations consist of a pair of second-order partial differential equations for the magnetic (electron) and ion stream functions, and Bernoulli equations for the density. It is found from the numerical results that the multi-grid method with the damped Jacobi method in the smoothing step is effective for solving these equations with numerical stability, high accuracy, and high speed.

Keywords: Two-fluid plasma, flowing equilibrium, spherical torus, multi-grid method, numerical analysis

DOI: 10.3233/JAE-171048

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 439-446, 2019

Authors: Miwa, Daiki | Takahashi, Yasuhito | Fujiwara, Koji | Higuchi, Shingo

Article Type: Research Article

Abstract: This paper describes a magnetic circuit design of an in-car low-cost current sensor, which is composed of a laminated core with air gap and a Hall sensor, using a finite-element method. First, a suitable structure of its iron core is examined from the standpoints of the linearity of detected flux density and the ease of its installation. In addition, the effect of eccentric position of a conducting wire and position displacement of the Hall sensor on the measurement accuracy is discussed.

Keywords: Current sensor, laminated core, finite-element method, homogenization method, eccentric position

DOI: 10.3233/JAE-171252

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 447-454, 2019

Authors: Traore, Papa Silly | Asfour, Aktham | Yonnet, Jean Paul | Boudinet, Cedric

Article Type: Research Article

Abstract: A new fully digital Giant Magneto-Impedance (GMI) sensor is presented. The design combines the off-diagonal configuration of the sensitive element with a real-time digital electronic conditioning based on a Software Defined Radio (SDR). Compared to a conventional implementation of these sensors, the proposed design exhibits key advantages. These include firstly the simplicity of obtaining a quasi-linear sensor response around the zero-field point without making use of a bias magnetic field and an offset cancelling device. Secondly, the potential of integration, the flexibility of reconfiguration as well as the low-noise and high-sensitivity are promising features of the developed concept. Noise performance …of 1.8 pT/Hz was obtained in the white noise region. Show more

Keywords: GMI sensors, off-diagonal, digital processing techniques

DOI: 10.3233/JAE-171214

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 455-463, 2019

Authors: Nabias, Julie | Asfour, Aktham | Yonnet, Jean Paul

Article Type: Research Article

Abstract: The influence of the temperature on the off-diagonal GMI sensors was studied. The sample was a Co-rich amorphous wire of 100 μm diameter and 5 cm long. The range of investigated temperature was [20 °C; 120 °C]. It included the industrial range. Particular attention was paid to the temperature dependence of the intrinsic sensitivity and offset of the off-diagonal component of the impedance tensor which are the most relevant parameters for the sensor implementation The results showed that the intrinsic odd symmetry of this off-diagonal component with respect to the zero field-point was not modified with temperature. The quasi-zero offset was also very …little changed. The sensitivity near the zero-field was increased with temperature by about 36%. Furthermore, a general comparison, based on previous reported results, with the diagonal component of the impedance tensor showed that sensitivity was increased in an almost similar way for both components, but the off-diagonal component clearly exhibited best offset stability. Show more

Keywords: GMI sensors, off-diagonal, temperature

DOI: 10.3233/JAE-171212

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 465-472, 2019