The ENEA conductor for the EU DEMO Nb3Sn toroidal field (TF) magnets, cooled by supercritical He, features a rectangular cross section with two small pressure relief channels ('holes'), separated from the cable bundle by means of a flat spiral, twisted together with the last cabling stage. A well-instrumented short sample of the ENEA TF conductor has been tested in SULTAN at SPC, Villigen (Switzerland) in 2016, aimed at its thermal-hydraulic characterization, and the test results are presented here. A correlation for the friction factor in the small holes is derived, best fitting the results of a set of computational fluid dynamics simulations. The new correlation (combined with existing correlations for the He friction factor in the bundle region) is shown to allow a proper reproduction of the measured hydraulic characteristic of the conductor. The heat slug propagation tests are used to calibrate the hole-to-bundle heat transfer coefficient in the 4C thermal-hydraulic code and to estimate the characteristic length for the homogenization of the He temperature on the conductor cross section, following a localized thermal perturbation.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
Bonifetto, R., Bruzzone, P., Corato, V., Muzzi, L., Savoldi, L., Stepanov, B., Zanino, R., & Zappatore, A. (2018). Thermal-Hydraulic Test and Analysis of the ENEA TF Conductor Sample for the EU DEMO Fusion Reactor. IEEE Transactions on Applied Superconductivity, 28(4), -. . https://doi.org/10.1109/TASC.2018.2821367