Analysis of thermo-hydraulic phenomena in CICC type cable with central cooling channel

1. Analiza zjawisk termo-hydraulicznychw kablu nadprzewodnikowym typu CICC z centralnym kanałem chłodzącym dr inż. Monika Lewandowska

2. Plan seminarium • Wprowadzenie • Cable in Conduit Conductors (CICC’s) • CICC’s w tokamaku ITER • Istota zjawiska termosyfonu • Charakterystyka badanej próbki • Opis eksperymentu • Wyniki • Perspektywy

3. Cable in Conduit Conductors (CICC’s) Scheme of the early CICC proposal Bundle Hole Modern realizations of CICCs to be applied in magnets for fusion technology

4. Przekrój typowej żyły kabla nadprzewodnikowego typu CICC

5. The ITER project • InternationalThermonuclearExperimentalReactor • Aim: produce energy from nuclear fusion • High magnetic field (11 T) to confine the hot plasma • Heavy heat loads on the coils due to neutron flux CICC’s mandatory!

6. CICC’s in ITER Central Solenoid:1152 Nb3Sn Strands, 13 T, 45 kA Toroidal Field Coil: 900 Nb3Sn + 522 Cu Strands, 68 kA, 11.3 T Poloidal Field Coil:1440 NbTi Strands, < 45 kA, < 6 T

7. Gravity-buoyancy effect in a dual channel CICC In a vertically oriented dual channel CICC with the coolant flowing downward, power deposition in the bundle region causes the reduction of the flow velocity due to the reduced density of helium. Eventually, the back-flow can occur, leading to quench.

8. Charakterystyka badanego kabla (ITER TF)

9. Schemat oprzyrządowania próbki

10. Fotografie oprzyrządowania próbki

11. Experimental setup SULTAN = SUpraLeitende TestANlage= Test facility for superconductors Supercritical He: Tinlet = 4.5 K or 6.5 K pinlet = 1 MPa = 10 g/s

12. Typical set of raw data

13. Results • We measured and analysed the temperature • deviations from the 1D model, which assumes • homogenous temperature in every cross • sectionn • After a heated region the deviations ΔT • disappear exponentially with distance. • The magnitude of ΔT is proportional to the • heating power per unit length and inversely to • the mass flow rate. • ΔTmaxmay be readily estimated from the • obtained results. R.Herzog, M.Lewandowska, M.Calvi, M.Bagnasco. C.Marinucci, P.Bruzzone, Helium flow and temperature distribution in a heated dual channel CICC sample for ITER, accepted for publication in IEEE Transactions of Applied Superconductivity

14. Assessment of the helium velocityinthecooling channel and inthebundle vH was estimated from the time delay between the rising edges of spot heater SHa current and TRa readings.

15. Frictionfactorcorrelations • Hole • ITER DDD • Zanino • Bundle • ITER DDD • Katheder • Porous medium D-F • Porous medium A h – spiral height, w – width, g – gap R. Zanino, et al., IEEE Trans. Appl. Supercon. 10 (2000) 1066-1069 H. Katheder, Cryogenics 34 (1994) 595–598 [ICEC supplement] M. Bagnasco, et al, CHATS AS 2008

16. Pressure drop and helium velocityin TFS experimental data and simulation

17. Pressure drop and flowvelocitiesexperimental data and final model

18. Heat transfer in the ITER TF conductor

19. Stationary two-channel model temperature in the cooling hole temperature in the cable bundle TB TH mH mB Constant thermophysical parameters phBH Analytical solution B.Renard, et al , Evaluation of thermal gradients and thermosiphon in dual channel cable-in-conduit conductors, Cryogenics 46 (2006) 629-642

20. Average heat transfer coefficient between bundle and hole C. Marinucci, et al, Analysis of the transverse heat transfer coefficients in a dual channel ITER-type cable-in-conduit conductor, Cryogenics 47 (2007) 563-576

21. Temperature profiles along the sampleexperimental data and simulation

22. Thank you for your attention