A new benchmark problem for electromagnetic modelling of superconductors: the high- T c superconducting dynamo
Authors
Brambilla, Roberto
Publication Date
2020-08-31Journal Title
Superconductor Science and Technology
ISSN
0953-2048
Publisher
IOP Publishing
Volume
33
Issue
10
Language
en
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Ainslie, M., Grilli, F., Quéval, L., Pardo, E., Perez-Mendez, F., Mataira, R., Morandi, A., et al. (2020). A new benchmark problem for electromagnetic modelling of superconductors: the high- T c superconducting dynamo. Superconductor Science and Technology, 33 (10) https://doi.org/10.1088/1361-6668/abae04
Abstract
Abstract: The high-T c superconducting (HTS) dynamo is a promising device that can inject large DC supercurrents into a closed superconducting circuit. This is particularly attractive to energise HTS coils in NMR/MRI magnets and superconducting rotating machines without the need for connection to a power supply via current leads. It is only very recently that quantitatively accurate, predictive models have been developed which are capable of analysing HTS dynamos and explain their underlying physical mechanism. In this work, we propose to use the HTS dynamo as a new benchmark problem for the HTS modelling community. The benchmark geometry consists of a permanent magnet rotating past a stationary HTS coated-conductor wire in the open-circuit configuration, assuming for simplicity the 2D (infinitely long) case. Despite this geometric simplicity the solution is complex, comprising time-varying spatially-inhomogeneous currents and fields throughout the superconducting volume. In this work, this benchmark problem has been implemented using several different methods, including H-formulation-based methods, coupled H-A and T-A formulations, the Minimum Electromagnetic Entropy Production method, and integral equation and volume integral equation-based equivalent circuit methods. Each of these approaches show excellent qualitative and quantitative agreement for the open-circuit equivalent instantaneous voltage and the cumulative time-averaged equivalent voltage, as well as the current density and electric field distributions within the HTS wire at key positions during the magnet transit. Finally, a critical analysis and comparison of each of the modelling frameworks is presented, based on the following key metrics: number of mesh elements in the HTS wire, total number of mesh elements in the model, number of degrees of freedom, tolerance settings and the approximate time taken per cycle for each model. This benchmark and the results contained herein provide researchers with a suitable framework to validate, compare and optimise their own methods for modelling the HTS dynamo.
Keywords
Paper, HTS dynamo, flux pump, coated conductor, numerical simulation, HTS modelling, high temperature superconductors
Relationships
Sponsorship
Consejo Nacional de Ciencia y Tecnologia and Secretaria de Energia de Mexico (541016/439167)
Engineering and Physical Sciences Research Council (Early Career Fellowship, EP/P020313/1)
NZ Royal Society Marsden Grant (MFP-VUW1806)
Identifiers
sustabae04, abae04, sust-104001.r1
External DOI: https://doi.org/10.1088/1361-6668/abae04
This record's URL: https://www.repository.cam.ac.uk/handle/1810/309880
Rights
Attribution 4.0 International (CC BY 4.0)
Licence URL: https://creativecommons.org/licenses/by/4.0/
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