Effective thermal conductivity in HTS coils

✍ Scribed by Jorma Lehtonen; Risto Mikkonen; Jaakko Paasi

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 183 KB
• Volume: 40
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(00)00030-8

✦ Synopsis

We present a numerical model to determine the eective thermal conductivity in high-T c superconducting (HTS) coils. The model, based on the heat conduction equation solved with the ®nite element method, will help us to compute the temperature dependence of the eective thermal conductivity in coils with varying proportions of epoxy in the total winding volume. The conductor parameters in the coils correspond to those in a real Bi-2223/Ag multi®lamentary composite tape, where the anisotropy of the Bi-2223 material has been taken into account. We will furthermore discuss about the eects of geometry of the composite structure on eective thermal conductivity. Our result shows that in epoxy impregnated HTS coils at temperatures below 60 K, the eective thermal conductivity is over two orders of magnitude higher in the parallel direction with the conductor axis compared to the perpendicular direction.