Pressure drop and transversal heat transfer in wendelstein 7-X superconductors

Abstract

In the Helitex test facility of KfK/ITP experimental investigations were performedof pressure drop and transversal heat transfer in the cable-in-conduit superconductor (CICC) for the Wendelstein 7-X magnet system. The friction factor is roughly three times the values in an equivalent smooth tube and can be described accurately by a modified Prandtl-Karman equation. Based on a new physical model, equations for the heat transfer between the flow channel and the jacket were derived which consider heat conduction and heat convection simultaneously. The measured thermal conductivity of the insulating layer between neighbouring conductors increases with increasing temperature and was correlated by an empirical equation.