Helium Flow and Temperature Distribution in a Heated Dual-Channel CICC Sample for ITER

A spare, 3.5 m long dual-channel cable-in-conduit conductor (CICC) section, made according to the most recent ITER toroidal-field coil design, allowed conducting dedicated thermo-hydraulic experiments in the SULTAN test facility. The sample was heated by eddy-current losses induced in the strands by an applied AC magnetic field as well as by strip heaters mounted on the outside of the conductor jacket. Temperature sensors mounted on the jacket surface, in the central channel and at different radii in the annular region revealed a detailed picture of the temperature distribution at different mass flow rates and heat deposition modes. A clear phenomenological description of the temperature deviations from the one-dimensional expectation emerged during the experiments. The measurement of the flow velocities in the central channel and in the annular region under several heat-load conditions led to further insights.