scholarly journals How to Choose the Superconducting Material Law for the Modelling of 2G-HTS Coils

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2679 ◽  
Author(s):  
Bright Chimezie Robert ◽  
Muhammad Umar Fareed ◽  
Harold Steven Ruiz

In an attempt to unveil the impact of the material law selection on the numerical modelling and analysis of the electromagnetic properties of superconducting coils, in this paper we compare the four most common approaches to the E-J power laws that serve as a modelling tool for the conductivity properties of the second generation of high-temperature superconducting (2G-HTS) tapes. The material laws considered are: (i) the celebrated E-J critical-state like-model, with constant critical current density and no dependence with the magnetic field; (ii) the classical Kim’s model which introduces an isotropic dependence with the environment magnetic field; (iii) a semi-empirical Kim-like model with an orthonormal field dependence, J c ( B ) , widely used for the modelling of HTS thin films; and (iv) the experimentally measured E–J material law for SuperPower Inc. 2G-HTS tapes, which account for the magneto-angular anisotropy of the in-field critical current density J c ( B ; θ ) , with a derived function similar to Kim’s model but taking into account some microstructural parameters, such as the electron mass anisotropy ratio ( γ ) of the superconducting layer. Particular attention has been given to those physical quantities which within a macroscopic approach can be measured by well-established experimental setups, such as the measurement of the critical current density for each of the turns of the superconducting coil, the resulting distribution of magnetic field, and the curve of hysteretic losses for different amplitudes of an applied alternating transport current at self-field conditions. We demonstrate that although all these superconducting material laws are equally valid from a purely qualitative perspective, the critical state-like model is incapable of predicting the local variation of the critical current density across each of the turns of the superconducting coil, or its non-homogeneous distribution along the width of the superconducting tape. However, depending on the physical quantity of interest and the error tolerance allowed between the numerical predictions and the experimental measurements, in this paper decision criteria are established for different regimes of the applied current, where the suitability of one or another model could be ensured, regardless of whether the actual magneto angular anisotropy properties of the superconducting tape are known.

1987 ◽  
Vol 99 ◽  
Author(s):  
S. Matsuda ◽  
M. Okada ◽  
T. Morimoto ◽  
T. Matsumoto ◽  
K. Ihara

ABSTRACTA tape-shaped wire with Y1 Ba2Cu3, O7-δ, core and Ag sheath was fabricated by a drawing-rolling method. The critical current density of the wire with 0.1 mm thickness and 6 mm width was in 2 the range of 2000 A/cm at 77 K in the absence of external magnetic field. Presence of 20 m Tesla magnetic field reduced the J value to 1/100.


1997 ◽  
Vol 71 (12) ◽  
pp. 1715-1717 ◽  
Author(s):  
Ryoji Funahashi ◽  
Ichiro Matsubara ◽  
Kazuo Ueno ◽  
Hiroshi Ishikawa ◽  
Katsunori Mizuno ◽  
...  

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3159-3164
Author(s):  
C. FERDEGHINI ◽  
M. R. CIMBERLE ◽  
G. GRASSO ◽  
P. GUASCONI ◽  
A. MALAGOLI ◽  
...  

We have developed a method that allows, by a simple set of magnetic measurements, to study the texturing of the grains inside a BSCCO-Ag tape. Because the texture is anisotropic we define the angle ϑ L that identifies the mean grain misalignment angle with respect to the tape surface in longitudinal direction (i.e. rolling direction) and the angle ϑ T in transverse direction. The technique is based on the assumption that, because of the very high anisotropy of the critical current density in BSCCO superconducting compounds, the magnetic moment is essentially generated by the current circulating in the a-b planes of the BSCCO grains. The different magnetisation cycles, measured when the orientation of the magnetic field with respect to the tape surface is changed, depend only on the grain orientation inside the tape, which determines the effective magnetic field component normal to the a-b planes of the grains. Here we present the texture evolution of the BSCCO grains inside silver sheated multifilamentary tape starting from the initial steps of the mechanical deformation up to the final heating stage. The results obtained from the magnetic method are compared with those obtained with other methods, i.e. X-ray diffraction and critical current density anisotropy. Also results obtained on samples prepared in different way will be presented.


1992 ◽  
Vol 170 (2) ◽  
pp. 549-562 ◽  
Author(s):  
D. Glatzer ◽  
A. Forkl ◽  
H. Theuss ◽  
H. U. Habermeier ◽  
H. Kronmüller

1991 ◽  
Author(s):  
G. Swaminathan ◽  
S. Rajendra Kumar ◽  
N. Ramadas ◽  
K. Venugopal ◽  
K. A. Durga Prasad ◽  
...  

1997 ◽  
pp. 843-846
Author(s):  
Kazutaka Yamamoto ◽  
Hiroko Onoda ◽  
Yutaka Yamada ◽  
Tsutomu Koizumi ◽  
Takayo Hasegawa ◽  
...  

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