Modeling study on high-temperature superconducting bulk's growth anisotropy effect on magnetization and levitation properties in applied magnetic fields

Fabricated by top-seeded melt-texture methods, high-temperature superconducting (HTS) bulk, such as YBaCuO bulk exhibits anisotropic properties of the critical current density J _c spatial distribution in growth sector regions and growth sector boundaries (GSBs). It was found that the YBaCuO bulk arrangement optimization considering the J _c spatial distribution above a permanent magnet guideway (PMG) enhances the levitation performance of the HTS magnetic levitation (maglev) system according to the past experiments. Therefore, from the point of view of practical applications, a theoretical model describing this HTS growth anisotropy is required to reproduce its effect on HTS maglev properties. In this study, we proposed an updated J _c spatial function with an adjustment parameter to better describe HTS bulk's growth anisotropy. Its Cartesian form is suitable for differently shaped bulk superconductors. We subsequently established a 3D simulation model of an HTS–PMG maglev system and completed the calculations of both the levitation force and decay of two different bulk arrangements above the PMG. The calculation results are consistent with the experimental results, which verifies the reliability of the 3D HTS–PMG maglev model and J _c spatial function. Further, all results show that a more stable HTS levitation with a larger levitation force is generated in the case where the GSB is aligned with the longitudinal direction of the PMG's largest magnetic field. This provides a reference for HTS maglev designs. Furthermore, the modeling can be a useful tool for optimizing the HTS–PMG maglev system for several scenarios. (paper)