Numerical modelling of superconducting composites in AC magnetic fields
Numerical modelling of superconducting composites in AC magnetic fields
This thesis is focused on numerical modelling of high-temperature superconductors (HTS) for the purpose of a better understanding of the loss mechanisms which occur in alternating magnetic fields and whose consequences still constitutes one of the remaining obstacles for practical applications of superconductivity.
For modelling infinite long tapes with rectangular cross-sections a simple 2D integral formulation developed by Brandt is used, which results in a stiff differential equation for the current density. To solve it, Rosenbrock method was implemented and validated.
A extensive part of this thesis is dedicated to the coupling effect between superconductors via a resistivity matrix, for which analytical calculations are limited to a very simple situation. Such 3D effect is modelled in superconductors with finite dimensions using the finite element method (FEM) software Flux3D. Due to the highly non-linear E-J law, initial tests using Flux3D showed the inefficiency of the linear system solver used at each Newton-Raphson step. To improve the general performance of Flux3D new iterative solvers, Gmres and Bi-CGStab, were implemented. FEM simulations were carried out to study the coupling phenomenon in strips and slabs superconductors.
For the particular case of infinite slabs or thin discs, the 3D coupling effect can be modelled by using a 2D formulation based on a extension of Brand’s formulation for the sheet current in thin finite superconductors. Being simpler than FEM, this method is found to be successful for modelling the coupling phenomenon at different applied fields, and therefore was used to analyze the influence of different geometrical and physical characteristics of superconductors on the coupling effect.
University of Southampton
Costa Bouzó, Marta
0fcdae6c-b42f-41fe-95bc-e6db62f66542
2004
Costa Bouzó, Marta
0fcdae6c-b42f-41fe-95bc-e6db62f66542
Costa Bouzó, Marta
(2004)
Numerical modelling of superconducting composites in AC magnetic fields.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
This thesis is focused on numerical modelling of high-temperature superconductors (HTS) for the purpose of a better understanding of the loss mechanisms which occur in alternating magnetic fields and whose consequences still constitutes one of the remaining obstacles for practical applications of superconductivity.
For modelling infinite long tapes with rectangular cross-sections a simple 2D integral formulation developed by Brandt is used, which results in a stiff differential equation for the current density. To solve it, Rosenbrock method was implemented and validated.
A extensive part of this thesis is dedicated to the coupling effect between superconductors via a resistivity matrix, for which analytical calculations are limited to a very simple situation. Such 3D effect is modelled in superconductors with finite dimensions using the finite element method (FEM) software Flux3D. Due to the highly non-linear E-J law, initial tests using Flux3D showed the inefficiency of the linear system solver used at each Newton-Raphson step. To improve the general performance of Flux3D new iterative solvers, Gmres and Bi-CGStab, were implemented. FEM simulations were carried out to study the coupling phenomenon in strips and slabs superconductors.
For the particular case of infinite slabs or thin discs, the 3D coupling effect can be modelled by using a 2D formulation based on a extension of Brand’s formulation for the sheet current in thin finite superconductors. Being simpler than FEM, this method is found to be successful for modelling the coupling phenomenon at different applied fields, and therefore was used to analyze the influence of different geometrical and physical characteristics of superconductors on the coupling effect.
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Published date: 2004
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Local EPrints ID: 465653
URI: http://eprints.soton.ac.uk/id/eprint/465653
PURE UUID: d81c84de-29ad-4b09-8f3f-da8866aad9fc
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Date deposited: 05 Jul 2022 02:24
Last modified: 16 Mar 2024 20:18
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Author:
Marta Costa Bouzó
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