Keywords :
Finite elements; H-φ formulation; magneto-thermal analysis; no-insulation coil; thin shell approximation; <inline-formula xmlns:ali="; > <tex-math notation="LaTeX">$\vec{H}$</tex-math> </inline-formula> −ϕ formulation; Coil; Conductivity; Finite element; Finite element analyse; High-temperature superconductor; Magneto-thermal analysis; No insulations; No-insulation coil; Perpendicular magnetic anisotropy; Thin shell approximation; Thin shells; Xmlns:mml="; Xmlns:xlink="; Xmlns:xsi="; Electronic, Optical and Magnetic Materials; Condensed Matter Physics; Electrical and Electronic Engineering; Physics - Accelerator Physics; Physics - Superconductivity; Computer Science - Computational Engineering; Finance; and Science
Abstract :
[en] For finite element (FE) analysis of no-insulation (NI) high-temperature superconducting (HTS) pancake coils, the high aspect ratio of the turn-to-turn contact layer (T2TCL) leads to meshing difficulties which result in either poor quality mesh elements resulting in a decrease of the solution accuracy or a high number of degrees of freedom. We proposed to mitigate this issue by collapsing the T2TCL volume into a surface and using a so-called thin shell approximation (TSA). Previously, two TSA have been introduced, one to solve the heat equation and the other for an H-φ magnetodynamic formulation. In this work, we propose to combine the magnetodynamic and thermal TSA to create a coupled magneto-thermal TSA for three-dimensional FE analysis. Particular attention is paid to the detailed derivation of the coupling terms. In the context of NI HTS pancake coils, the TSA represents the electric and thermal contact resistance of the T2TCL. For the HTS coated conductor (CC) itself, an anisotropic homogenization is used which represents its multi-layered structure. In axial and azimuthal direction, it resolves the current sharing between the HTS and other layers of the CC. The coupled TSA formulation is verified against a reference model with volumetric T2TCL. The coupled TSA is shown to significantly reduce the solution time as well as the manual effort required for high-quality meshes of the T2TCL. The implementation is open-source and a reference implementation is made publicly available.
Funding text :
The work of Erik Schnaubelt was supported in part by the Wolfgang Gentner Programme of the German Federal Ministry of Education and Research under Grant 13E18CHA and in part by the Graduate School Computational Engineering within the Centre for Computational Engineering at the Technical University of Darmstadt.
Commentary :
Presented at EUCAS 2023, Bologna, Italy. This work has been submitted
to the IEEE for possible publication
Scopus citations®
without self-citations
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