3D modeling of high-T_csuperconductors by finite element software

Abstract

A three-dimensional (3D) numerical model is proposed to solve the electromagnetic problems involving transport current and background field of a high-T c superconducting (HTS) system. The model is characterized by the E-J power law and H -formulation, and is successfully implemented using finite element software. We first discuss the model in detail, including the mesh methods, boundary conditions and computing time. To validate the 3D model, we calculate the ac loss and trapped field solution for a bulk material and compare the results with the previously verified 2D solutions and an analytical solution. We then apply our model to test some typical problems such as superconducting bulk array and twisted conductors, which cannot be tackled by the 2D models. The new 3D model could be a powerful tool for researchers and engineers to investigate problems with a greater level of complicity.

Electromagnetic behaviors of superconducting Nb3Sn wire under a time-dependent current injection

“…14,15 In this work, we intend to build a 3D model to analyze the performance degradation and AC loss of Nb 3 Sn superconducting strands; however, rare experiments are available for comparison to our simulation. Prior to implementing 3D modelling, it is necessary to validate the proposed approach by comparing its results with the corresponding 2D scenario.…”

“…2 In recent years, attempts have been made to study the electromagnetic behaviors of some superconductors by numerical simulation. [3][4][5][6][7][8][9][10][11][12][13][14][15][16] As for finite element modelling (FEM), the extreme complexity of hierarchical geometry and structure of Nb 3 Sn strand and CICC requires a special concern for the modelling of the strand entity. Therefore this will inevitably consume large amounts of CPU time and memory capacity in meshing and calculating process.…”

“…So, 2D simulations mainly focus on high-temperature superconductors (HTS) with homogenous material and standard bulk shape. 3,4,6,[8][9][10][11][13][14][15] As the advance of computer technology, it becomes feasible to use FEM to cope with Nb 3 Sn strand at the cost of long-time computation and large memory. Even so, modelling the strand down to filament level is still troublesome.…”

Numerical study of AC loss of two-layer HTS power transmission cables composed of coated conductors with a ferromagnetic substrate

“…The gap between adjacent tapes in each layer is determined by Eqs. (6)- (8) in [16], substituting the width of coated conductors w SC , number of tapes N , and the inner, R i , and outer, R o , radii with the values in Table 1. We regarded only the 2π/N tape part of the two-layer cable due to the periodicity in the cross-section.…”

“…Moreover, the experimental setup for superconducting cables is very costly and time-consuming. Therefore, using the finite-element method (FEM) in the simulation of AC loss of superconducting power transmission cables, instead of experimental work, has been preferred by many researchers [6][7][8][9][10]. Simulations of cables have also been useful for predicting and understanding the measured loss mechanism for either transport or magnetization loss [11,12].…”