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How to Choose the Superconducting Material Law for the Modelling of 2G-HTS Coils.
Materials (Basel) 2019; 12(17)M

Abstract

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.

Authors+Show Affiliations

Department of Engineering and Leicester, Institute for Space & Earth Observation Science, University of Leicester, Leicester LE17RH, UK.Department of Engineering and Leicester, Institute for Space & Earth Observation Science, University of Leicester, Leicester LE17RH, UK.Department of Engineering and Leicester, Institute for Space & Earth Observation Science, University of Leicester, Leicester LE17RH, UK. dr.harold.ruiz@leicester.ac.uk.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31443403

Citation

Robert, Bright Chimezie, et al. "How to Choose the Superconducting Material Law for the Modelling of 2G-HTS Coils." Materials (Basel, Switzerland), vol. 12, no. 17, 2019.
Robert BC, Fareed MU, Ruiz HS. How to Choose the Superconducting Material Law for the Modelling of 2G-HTS Coils. Materials (Basel). 2019;12(17).
Robert, B. C., Fareed, M. U., & Ruiz, H. S. (2019). How to Choose the Superconducting Material Law for the Modelling of 2G-HTS Coils. Materials (Basel, Switzerland), 12(17), doi:10.3390/ma12172679.
Robert BC, Fareed MU, Ruiz HS. How to Choose the Superconducting Material Law for the Modelling of 2G-HTS Coils. Materials (Basel). 2019 Aug 22;12(17) PubMed PMID: 31443403.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - How to Choose the Superconducting Material Law for the Modelling of 2G-HTS Coils. AU - Robert,Bright Chimezie, AU - Fareed,Muhammad Umar, AU - Ruiz,Harold Steven, Y1 - 2019/08/22/ PY - 2019/07/25/received PY - 2019/08/16/revised PY - 2019/08/19/accepted PY - 2019/8/25/entrez PY - 2019/8/25/pubmed PY - 2019/8/25/medline KW - alternating current (AC) losses KW - superconducting coil KW - superconducting material law JF - Materials (Basel, Switzerland) JO - Materials (Basel) VL - 12 IS - 17 N2 - 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. SN - 1996-1944 UR - https://www.unboundmedicine.com/medline/citation/31443403/How_to_Choose_the_Superconducting_Material_Law_for_the_Modelling_of_2G_HTS_Coils_ L2 - http://www.mdpi.com/resolver?pii=ma12172679 DB - PRIME DP - Unbound Medicine ER -
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