Magnetic Levitation Characteristics of the System of Permanent Magnet Stacks of HTS Tapes of Various Architectures

• Published in: Physics of atomic nuclei 2021-12, Vol.84 (12), p.1982-1990
• Main Authors: Anischenko, I. V., Osipov, M. A., Pokrovskii, S. V., Abin, D. A., Starikovskii, A. S., Rudnev, I. A.
• Format: Article
• Language: English
• Subjects: Checkout; Configurations; Cooling; Cooling systems; Critical current (superconductivity); Cryogenic cooling; Energy storage; Engineering Design of Nuclear Physics Equipment; Finite element method; Force and energy; Heat; Heat transfer; High temperature; High temperature superconductors; Insertion; Kinetic energy; Liquid nitrogen; Magnetic fields; Magnetic levitation; Magnetic levitation systems; Magnets, Permanent; Mathematical analysis; Parameters; Particle and Nuclear Physics; Permanent magnets; Physics; Physics and Astronomy; Silver; Stacks; Substrates; Superconducting tapes; Thermal conductivity; Thermal properties; Thermodynamic properties
• ISSN: 1063-7788; 1562-692X
• DOI: 10.1134/S1063778821100045

Stacked composite high-temperature superconducting tapes (HTS tapes) are advanced material for development of magnetic levitation systems such as levitation transport, bearings, and kinetic energy storage. At use of superconductor in variable fields, energy losses owing to existence of heat in superconductor leading to decrease in critical current and, as a consequence, in the levitation force are inescapable. One of the key advantages of stacks of HTS tapes over traditional bulk HTS is the presence of a metal substrate and layers of silver and copper, which leads not only to high strength but also to suitable thermal conductivity of the stacks, which makes it possible to remove released heat efficiently. Investigation of mechanisms of control of thermal properties of the systems, as well as development of efficient methods of checkout of heat transfer parameters of the system at various rates of insertion of an external magnetic field, is a relevant objective. The results of calculation of the behavior of the stack of HTS tapes in an external magnetic field by the finite element method accomplished with use of the Comsol Multiphysics software package are presented in this work. Investigations of control of thermal properties of a levitation system are carried out, and also efficient methods of checkout of the parameters of heat transfer of the system at various rates of insertion of external magnetic field are developed. It is demonstrated that improvement of thermal and, as a consequence, levitation properties of the system can be achieved by the effect of both change in architecture of the stacks themselves and use of various configurations of the cryogenic cooling system. Various alternatives of implementation of the cryocooler cooling system and also various configurations of the stacks at liquid-nitrogen cooling are discussed. It is demonstrated that liquid nitrogen cooling is efficient so far as the change in temperature in the system is less than 3 K. In the case of liquidless cooling of the stack, the configuration with lateral cooling is optimal. The presence of a mechanical cooling passage in the form of a hole in the case of low rates of insertion of the magnetic field either leads to degradation of the system or does not have an effect on its properties. At increase in the rate of insertion of the external magnetic field, the presence of the mechanical cooling passage leads to increase in the maximum levitation force.