APEX Task II Overview

1. APEX Task II Overview Neil Morley for theAPEX Task II Participants APEX E-Meeting August 7, 2001

2. Overview • Modeling- UCLA Codes- Hypercomp Phase II SBIR- Truchas with LANL • Experiments- MTOR - FLIHY • Other Work and Collaborations

3. New Modeling Work at UCLA Complimentary 3D Formulations for Flow3D benchmarking and Task I analysis A – Electric Potential Formulation B – Induced Magnetic-Fields Formulation Presented by Hulin Huang and Sergey Smolentsev

4. HyPerComp Phase-II SBIR Research • To convert HyPerComp’s existing adaptive hybrid unstructured mesh • environment to problems in liquid metal MHD with free surfaces. • Modular code structure to the extent possible, for hierarchical MHD treatment • Interaction with interested research groups (LANL, LLNL, FZK, etc.) • Commercial applications to metallurgy (MAG/GATE: Concept Engineering Group, PA) HIMAG : “HyPerComp Incompressible MHD ( HyPEX) Adaptive Grid ” suite of codes containing High Power Extraction code environment for nuclear fusion CAD/Grid generation PC-cluster based parallel computing Domain decomposition

5. v ~ j n ( i,j ) Summary of numerics Flow solver : Pressure-Implicit Splitting of Operators (PISO), R.I.Issa, 1985 - A non-iterative pressure correction scheme, recently implemented on unstructured meshes for free surface flows (Ubbink and Issa, 1999, Imperial College, UK) Free surface capture using Volume Of Fluid technique with higher order extensions ( Adaptive meshes, CIC-SAM, LANL procedures) Front tracking will be explored as an option MHD models: Source term based models * B = constant, E = 0 * B = constant, E = - * B varies along x Integrated NS/Maxwell equations * Ideal MHD σ =  * Real MHD Heat transfer and turbulence * Conduction and radiation flux at free surface * Turbulence models

6. Near-term Strategies Engineering must take precedence over mathematical completeness due to the time-bound nature of this project. Programmatic consultations with technical groups will be pursued. Mixed-analytical and numerical treatment of wall regions seem to hold promise for Hartmann number limitations. Parallel computations using hybrid meshes permit additional freedom in resolving Hartmann layers. Boundary condition procedures in induced field formulations pose a variety of problems. A relative study of simple BC assumptions must be performed initially and guide future research Elaborate implicit treatment must be available. At least: * Euler fully implicit * Crank-Nicholson * Hybrid, as in approx. projection methods of Kothe At the end of approximately the first 6 months effort, UCLA’s involvement at the code level may be initiated. Primary input from UCLA will be in the areas of MHD and interfacial transport * An independent investigation on the Hartmann number limitation + consequences * Advise on turbulence modeling issues * Models and boundary condition procedures for MHD

7. Collaboration with LANL on Truchas Code (Telluride) • Large Scale Parallelism • 1000+ CPUs • via domain decomposition • innovative solution algorithms • Will use initially for:- studying circulation in droplets- test unstructured MHD models- compare with FLOW3D Decomposition of part for parallel computation

8. Physical Models in Telluride • Incompressible Navier-Stokes Flow • Variable density owing to multiple fluids bounded by interfaces • Boussinesq approximation for density-temperature dependence • Multiple fluid, single-field model: multiple species per fluid • Turbulence: simple Prandtl mixing length model • Fluid interfaces • Kinematics: volume tracking representation • Surface tension: volumetric force (normal and tangential) • Interior “nonflow” regions • Voids • Conducting stationary solids: rigid and thermoelastic • Conducting moving solids (solidifying fluids) • Heat transfer • Conduction, convection (radiative BCs) • Interior gap resistance • Liquid/solid phase change with micro-structural models • Thermo-mechanical solid response (under development) • MHD: quasi-static approximation (just started!)

9. Current Status M-TOR Facility Systems • PPPL DC power supply and 24 coil torus tested up to 3000 A (B = 0.5 T). Trouble shooting underway to reach full 3600 A. • Water coolant loop installed and tested. Over temperature sensing systems currently being installed • Pumped flow loop nearly complete. Leak testing and flowmeter calibration to proceed this month. • 16 L Ga-In-Sn alloy arrived from Russia and introduced to pressure-dispensed storage tank. • Safety consultation with GA completed Ga-In-Sn flowing in open channel

10. MTOR – Arial View 1.4 m

11. Coil support plate • Magnet Coils EM Pumped Flow Loop for MTOR • Main • Bypass • Collection Reservoir • Electromagnetic Pump • Storage Reservoir • Heat Exchangers

12. Positive Electrode NegativeElectrode Free Surface B Ultrasound Transducer LM In @ Q = 0.05 l/s LM Out Preliminary Experiments for Inclined Plane Flow with Magnetic Propulsion Bmax = 0.45 T L = 45 cm

13. B = 0, I = 0 B = 0.5 – 0.2, I = 14A

14. Ultrasound measurements indicate reduction in flow height h1 = 8.43 mm with no parallel current h2 = 8.08 mm with 14 A parallel current (5.8 x 104 A/m2) h = 0.35 mm Abscissa divisions: 0.548 mm/div I = 14 A I = 0 A

15. Visual observations • Most surface waves disappear as field comes up. No large instabilities visible due to field gradient • Remaining surface waves disappear and liquid level visibly decreases near inlet as current comes up. • Rapid change in current splashed the liquid out of the channel

16. MTOR Small inclined plane tests

17. New inclined plane test section • Multiple, movable ultrasound height sensors • Variable side wall position, inclination angle and inlet nozzle height • Electrically isolated for applied current control (0-150A)

18. MHD Tests in NSTX conditions Flux horns for field concentration (B=0.8 T) and directional variation

19. MHD Tests of Soaker Hose for NSTX • Preliminary schematic of first soaker hose test in MTOR • 3 slotted tubes can be rotated as a block to change field orientation

20. Cryo-cooling of MTOR coil N2 cooling of MTOR coil down to vapor temp of –45 C gave a factor of 2 drop in conductivity.

21. Current Status FLIHY Facility Systems • Pumping station, flow meter and 4 m straight test section installed and operating • IR heater system installed and operating (40 kW/m2) • Ultrasound and IR camera diagnostics working, techniques continue to be evolved • Dye injection system being redesigned Flow direction Water Film flowing under IR heater

22. FLIHY Test Area – Free surface test section 4 m

23. FLIHY - Free surface test section Flow direction~ 8 m/s

24. FLIHY Free surface test section Shielded IR heater First Experiments on Free Surface Turbulent Heat Transfer Underway IR study of surface cooling as a function of flow height, velocity and inclination Will be summarized by Sergey Smolentsev and Brent Freeze IR image of water surface emerging from IR heater section

25. PISCES Plasma Column PISCES Plasma Column Other work • Plasma wind tests in PISCES - Collaboration with G. Antar and R. Doerner (UCSD) • Modeling of DIII-D lithium sample movement – Collaboration with D. White and C. Wong (GA) • FLIHY closed channel flow influence of MHD – Jupiter II collaboration with Japan Flowing film and stagnant boat tests in PISCES