Numerical simulation of bulk superconductor during pulsed field magnetization based on multi-field coupled analysis

Abstract

High-temperature bulk superconductors are widely used in various superconducting devices due to their high critical current density, which enables them to trap high magnetic fields. However, the critical current density of bulk superconductors is influenced by magnetic field, temperature and stress, and both increase of stress and temperature can lead to a decrease in the critical current density. And the influence of magnetic field, current, stress are interactional. In this paper, the multi-field coupled analysis is employed to investigate the electromagnetic and mechanical behavior on bulk superconductor during pulsed field magnetization. The simulation results were compared with the present experimental results. The results showed a good agreement between the simulation and experimental results, further validating the reliability of the numerical simulation method. The magnetic field, current, temperature, and stress distribution and variation within the bulk sample during the pulsed magnetization process were calculated and analyzed. Additionally, the influence of the central crack and edge crack in the bulk superconductor was investigated. The results indicate that the region near the crack experiences a variation in current flow direction, resulting in local temperature rise and significant electromagnetic forces. The tip of the crack exhibits stress concentration, leading to a decrease in critical current density. Bulk supercondutor with edge crack case exhibits greater stress concentration compared to those with central crack case. The impact of crack length on maximum stress was analyzed, revealing that as the crack length increases, both the maximum hoop stress and radial stress within the bulk sample rise.