Theoretical analysis of heat transport in tilted stacks of HTS tapes at temperatures above 20 K

Abstract

Tilted stacks of HTS tapes show favourable properties in terms of magnetisation. Magnetised stacks can be applied in superconducting rotating machines. In such case they will be subjected to varying magnetic fields and heat generation will occur. Therefore it is important to understand heat transfer in anisotropic structure of a stack to avoid overheating and optimise the shape for maximum magnetisation.To analyse the heat transfer a computational procedure to find components of anisotropic thermal conductivity is developed and compared with existing experimental data. The material parameters ready to use in other analyses are provided. Anisotropy of the structure of the HTS tapes plays crucial role in definition of the thermal behaviour of the investigated elements.The thermal behaviour of the stacks with different angles of tilt is investigated with a numerical model. Results show that the geometry of the stack significantly affects heat transfer. Analytical formulas describing the thermal behaviour of the stack depending on its dimensions are developed. The method to increase the speed of calculations by homogenising the stack is presented and its accuracy assessed.