Numerical analysis of AC losses in high T/sub c/ superconductors based on E-j characteristics represented with n-value

Amemiya, Naoyuki; Miyamoto, Koichi; Banno, N.; Tsukamoto, O.

doi:10.1109/77.621008

Cited by 90 publications

(46 citation statements)

References 2 publications

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“…An alternative approach involves modeling the superconductor with a highly nonlinear E-J constitutive law E ϰ J n , with n being a large number. [38][39][40] Such a relation can be incorporated within commercial finite-element method ͑FEM͒ software used for simulating physical processes based on partial differential equations ͑PDEs͒. Within this context, a general method of analyzing numerically the electromagnetic behavior of hightemperature superconductors subjected to time-varying magnetic fields was proposed recently by Hong and co-workers [41][42][43][44] .…”

Section: Introductionmentioning

confidence: 99%

Behavior of bulk high-temperature superconductors of finite thickness subjected to crossed magnetic fields: Experiment and model

et al. 2007

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Crossed-magnetic-field effects on bulk high-temperature superconductors have been studied both experimentally and numerically. The sample geometry investigated involves finite-size effects along both ͑crossed-͒ magnetic-field directions. The experiments were carried out on bulk melt-processed Y-Ba-Cu-O single domains that had been premagnetized with the applied field parallel to their shortest direction ͑i.e., the c axis͒ and then subjected to several cycles of the application of a transverse magnetic field parallel to the sample ab plane. The magnetic properties were measured using orthogonal pickup coils, a Hall probe placed against the sample surface, and magneto-optical imaging. We show that all principal features of the experimental data can be reproduced qualitatively using a two-dimensional finite-element numerical model based on an E-J power law and in which the current density flows perpendicularly to the plane within which the two components of magnetic field are varied. The results of this study suggest that the suppression of the magnetic moment under the action of a transverse field can be predicted successfully by ignoring the existence of flux-free configurations or flux-cutting effects. These investigations show that the observed decay in magnetization results from the intricate modification of current distribution within the sample cross section. The current amplitude is altered significantly only if a field-dependent critical current density J c ͑B͒ is assumed. Our model is shown to be quite appropriate to describe the cross-flow effects in bulk superconductors. It is also shown that this model does not predict any saturation of the magnetic induction, even after a large number ͑ϳ100͒ of transverse field cycles. These features are shown to be consistent with the experimental data.

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Section: Introductionmentioning

confidence: 99%

Behavior of bulk high-temperature superconductors of finite thickness subjected to crossed magnetic fields: Experiment and model

et al. 2007

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“…So, 2D simulations mainly focus on high-temperature superconductors (HTS) with homogenous material and standard bulk shape. 3,4,6,[8][9][10][11][13][14][15] As the advance of computer technology, it becomes feasible to use FEM to cope with Nb 3 Sn strand at the cost of long-time computation and large memory. Even so, modelling the strand down to filament level is still troublesome.…”

Section: Introductionmentioning

confidence: 99%

“…2 In recent years, attempts have been made to study the electromagnetic behaviors of some superconductors by numerical simulation. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] As for finite element modelling (FEM), the extreme complexity of hierarchical geometry and structure of Nb 3 Sn strand and CICC requires a special concern for the modelling of the strand entity. Therefore this will inevitably consume large amounts of CPU time and memory capacity in meshing and calculating process.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the excellent transport performance and mature production technology, Nb 3 Sn strands have been widely used in medical, scientific and technological areas, such as nuclear magnetic resonance spectrometer, human medical imaging systems, particle accelerators and ITER (International Thermonuclear Experimental Reactor). In ITER magnet system, the strands are twisted at several stages to form CICC (cable-in-conduit-conductors), carrying a high current (∼68KA) to generate a strong magnetic field (∼13T) to confine the plasma.…”

Section: Introductionmentioning

confidence: 99%

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Electromagnetic behaviors of superconducting Nb3Sn wire under a time-dependent current injection

Gao

2014

AIP Advances

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We build a 3D model to analyze the electromagnetic behaviors of Nb3Sn filamentary strand exposed to a time-varying current injection, under the consideration of n value and strain effect. Electromagnetic behaviors, performance degradation and AC loss are investigated. Results show that the filament bundles prevent a further field penetration from the outer shell into the interior matrix. Different current/field profiles occur in the strand and outside. Compared to the critical current, the average transport current keeps a high value with little change over a broader strain range, and has a larger magnitude by several orders of magnitude. Increasing the strain results in a suppression of the current transport capacity, and part of the current is expelled into the metal matrix causing larger AC loss. The larger twist pitch implies a longer current circuit and more magnetic flux enclosed, thus increasing the loss. More details are presented in the paper.

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“…Nonlinear E − J relations like E = E c (J /J c ) n have been implemented in the many commercial FEM software packages to solve Faraday (H-formulation) or Ampere (A-V formulation) equations [29,30]. Parameter n takes higher values than 20-25 for the coated conductors.…”

Section: General Description Of the Modelmentioning

confidence: 99%

Numerical study of AC loss of two-layer HTS power transmission cables composed of coated conductors with a ferromagnetic substrate

Yıldız¹,

İnanır²,

Çiçek³

et al. 2017

Turk J Elec Eng & Comp Sci

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This work includes the simulation of hysteretic AC losses in two-layer HTS power transmission cables made of second-generation high-temperature superconducting tapes with a ferromagnetic substrate subject to an oscillating AC transport current, calling upon the COMSOL Multiphysics finite-element software program and exploiting an AC/DC module. How the AC transport loss is influenced by the arrangement of tapes, as well as the optimized design of superconducting power cables based on YBCO-coated conductors, are investigated. According to the radial arrangement of the tapes, four different orientations of ferromagnetic substrate are considered: 1) out-in (substrate of inner/outer layer facing outward/inward), 2) in-out (substrate of inner/outer layer facing inward/outward), 3) in-in (substrates of both inner and outer layers facing inward), and 4) out-out (substrates of both inner and outer layers facing outward).We found that the AC loss of the superconducting layer for the out-in arrangement is the lowest. We also compare our calculations with experimental results.

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Numerical analysis of AC losses in high T/sub c/ superconductors based on E-j characteristics represented with n-value

Cited by 90 publications

References 2 publications

Behavior of bulk high-temperature superconductors of finite thickness subjected to crossed magnetic fields: Experiment and model

Behavior of bulk high-temperature superconductors of finite thickness subjected to crossed magnetic fields: Experiment and model

Electromagnetic behaviors of superconducting Nb3Sn wire under a time-dependent current injection

Numerical study of AC loss of two-layer HTS power transmission cables composed of coated conductors with a ferromagnetic substrate

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