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THERMOFLUID MHD for ITER TBM. CURRENT STATUS

THERMOFLUID MHD for ITER TBM. CURRENT STATUS. By UCLA Thermofluid MHD GROUP Presented by Sergey Smolentsev US ITER TBM Meeting UCLA May 10-11, 2006. Presentation layout. MHD and Heat Transfer in the H-H phase Electromagnetic coupling in poloidal ducts PbLi manifold experiment

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THERMOFLUID MHD for ITER TBM. CURRENT STATUS

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  1. THERMOFLUID MHD for ITER TBM. CURRENT STATUS By UCLA Thermofluid MHD GROUP Presented by Sergey Smolentsev US ITER TBM Meeting UCLA May 10-11, 2006

  2. Presentation layout • MHD and Heat Transfer in the H-H phase • Electromagnetic coupling in poloidal ducts • PbLi manifold experiment • Buoyancy effects modeling • 2-D MHD turbulence modeling • Near-future plans

  3. MHD and Heat Transfer in H-H • PbLi enters the module at 470C • He enters the module at 300C • Only surface heat flux • U=10 cm/s • Steady state • “Low conductivity grade” SiC/SiC (=1-50, k=1-5) ----------------------------------------------------------- Issues addressed: • Heat exchange between He and PbLi • Effect of FCI (, k) and flow regime on heat transfer • Heat leakage into He • T across the FCI

  4. =5 =1 =50 (lam) =50 (turb) MHD calculations • Fully developed flow model • Only one channel (front row, middle) is considered • Parametric analysis, FCI=1-50 S/m • Laminar flow (=1; 5; 50) • Turbulent flow (=50) MHD velocity profiles at B=4 T

  5. Heat transfer calculations • Velocity profile from the MHD calculations • Temperature and h in the He flows from the He analysis • Parametric calculations of the 3-D temperature field, using k and  as parameters Typical temperature field in H-H in the poloidal flow at U=10 cm/s

  6. Heat exchange between He and PbLi • Calculate temperature field in He, assuming only surface heat flux • Calculate temperature in PbLi • Calculate heat losses from PbLi into He • Repeat temperature calculations in He taking into account heat losses from PbLi • Go to step 2 Iterate until no changes occur

  7. Heat exchange between He and PbLi • Iteration 1: no heat leakage assumed • Iteration 2: First wall: 0.063 Mw/m2 Divider plate: 0.055 Top plate: 0.050 Bottom plate: 0.050 Grid plates: 0.045 Side walls: 0.059 • Iteration 3: to be performed Tbulk at =5 S/m, k=5 W/m-K

  8. Temperature drop across FCI Front FCI: SiC=5 S/m, kSiC=5 W/m-K • Max TFCI < 120 K • No effect of  (laminar) Toroidal distance, m

  9. Heat leakage into He k=1, =1; 5;50 k=5, =1; 5;50 k=5, =50 (turb) • No effect of  (laminar) • Turbulence is important • TPbLi~(10-40) K

  10. Conclusions on heat transfer. Discussion issues. • Iterative procedure coupling heat transfer in He and PbLi has been established • Thermofluid MHD analysis has been performed in H-H assuming “low conductivity grade” SiC/SiC • Turbulence is important • What SiC/SiC we are looking for and what SiC/SiC will be achievable in the neat future? • What to do next? (D-T, comparison with DEMO, unsteady conditions, more emphasis on MHD turbulence and buoyancy effects, meaningful experiments)

  11. Electromagnetic coupling • Goal: near uniform flow distribution • Flows are electromagnetically coupled • How changes in one flow will affect other flows? • Planning: Modeling for (1-2),(1-2-3), (2-5) in normal and abnormal conditions No ! Yes 4 5 6 1 2 3

  12. Manifold experiment • The test-article models “real” flow in the TBM, including the inlet and outlet section and three poloidal channels • (Exp. A) Non-conducting and (Exp. B) conducting test-article • Measurements: Pi, Qi, , V • Q1: Is the flow distributed uniformly? • Q2: Do we need FCI in the inlet and outlet sections? • (Exp. C) Manifold optimization • Status: pre-fabrication Goal:Manifold design that provides uniform flow distribution and minimizes the MHD pressure drop

  13. Modeling buoyancy effects • Significant effect on heat transfer • MHD: transition to 2-D; reduction of circulation flow • High Ha, high Gr. Computations are very time consuming • Using periodic BC and FFT reduces the computational time by a few orders (compared to a relaxation technique) • Status: testing ITER: Ha=6350 Gr=1.5109 DEMO: Ha=14,900 Gr=2.5 1012 Before using FFT: Ha=102-103, Gr=107 Goal:  2 to 5 orders in Gr 1 order in Ha B

  14. Modeling 2-D MHD turbulence • Significant effect on heat transfer • 0-equation turbulence model is used (my be inaccurate) • Implementation of 2-equation model is in progress

  15. Near-future plans • Readdress MHD/heat transfer in DEMO, looking at similarities and differences with ITER • Perform MHD/heat transfer analysis in DT • Iterate with others (He, SiC/SiC, design, stress) to narrow the uncertainties • Keep working on modeling (electromagnetic coupling, buoyancy effects, 2-D MHD turbulence) • Keep working on the manifold experiment

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