Thermal-hydraulics

in super-conducting cables and magnets

Introduction · Thermal-hydraulics constitutes an important subject in the field of applied superconductivity and cryogenics, and a strongly inter-disciplinary topic of current research, with particular reference to fusion magnets applications (e.g., the International Thermonuclear Experimental Reactor --ITER). · The tasks to be solved by the modeler concern the refrigeration of super-conductors and include the study of the evolution of thermal-hydraulic transients in complex systems with nonlinearly coupled solids and fluids. The solution of these issues is essential for the proper design and operation of very expensive components. · Timescales to be considered range from the very short, stability timescale, to intermediate, quench timescales, to long-timescale phenomena, e.g. the cool-down of an entire magnet.		Typical ITER cable-in-conduit conductor
The ITER Central Solenoid Model Coil Testing Group on April 19^th, 2000, just after the successful completion of the DC charging tests at JAEA Naka, Japan. Participants to the 12^th ITER Toroidal Field Model Coil Test and Analysis Meeting (Cadarache, France, October 2000).	Major achievements · Development of a 1-D 2-fluid model (àMITHRANDIR code) for the analysis of thermal-hydraulic transients in a single dual-channel cable-in-conduit conductor cooled by helium I or II, its validation against data from QUELL, FSJS, and other experiments, and its application to the ITER design · Development and validation of quasi 3-D models for coupled conductors within a coil (à M&M code) and for localized phenomena on the conductor cross section (à M^3 code). · Application of the codes to the analysis of different transients (e.g., current sharing temperature measurement and DC performance assessment, AC losses measurement, stability and quench tests, hydraulic characterization), after participation to all the experimental campaigns on the ITER Model and Insert Coils. · Development and validation of the Cryogenic Circuit, Conductor and Coil -- 4C code against data from different magnet systems, spanning from fast discharge to week-long cool-down. The extensive application of the code to the ITER magnet system is presently ongoing. · Development of the thermal-hydraulic module of the THELMA code, for the integrated thermal-hydraulic electromagnetic simulation of ITER cable-in-conduit conductors. Validation and application of the resulting tool to the analysis of transients where the effects of current unbalance/redistribution are relevant · CFD analysis of basic transverse transport phenomena in ITER CICC (using the FLUENT code) as well as of heat exchangers for the high temperature superconducting current leads (using the STAR CCM+ code)
Past and present collaborations · In Italy: ENEA Frascati, Politecnico di Milano, Universita’ degli Studi di Bologna, Universita’ degli Studi di Udine. · Abroad: CEA Cadarache (France), CRPP Villigen (Switzerland), F4E Barcelona (Spain), ITER IO Cadarache (France), USIPO Oak Ridge (USA), JAEA Naka (Japan), KIT Karlsruhe (Germany), NFRI Daejeon (Korea), PSFC – MIT Cambridge (USA).