Slide 1

APEX Task II Overview

Neil Morley for theAPEX Task II Participants

APEX E-Meeting

August 7, 2001

Slide 2

Overview

• Modeling- UCLA Codes- Hypercomp Phase II SBIR- Truchas with LANL

• Experiments- MTOR - FLIHY

• Other Work and Collaborations

Slide 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

][2 BU ][ BUj

BUUBBt

B)()(

1 2

0

)'(

1

0Bj

Slide 4

• 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)

HyPerComp Phase-II SBIR Research

HIMAG : “HyPerComp Incompressible MHD( HyPEX) Adaptive Grid ” suite of codes

containing High Power Extraction code environment for nuclear fusion

CAD/Grid generation

Domain decomposition

PC-cluster based parallel computing

Slide 5

Summary of numerics

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

y

Bu

x

Bv zz

2

xm

zyx

xz

xyb

mxb

Bz

uB

y

uB

t

B

uz

BB

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BBR

x

BRPu

t

u

2

2

22

Re

1

Re

1

/

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

n ~(i,j)

Slide 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

Slide 7

• 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 partfor parallel computation

Collaboration with LANL on Truchas Code (Telluride)

Slide 8

• 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!)

Physical Models in Telluride

Slide 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

Slide 10

MTOR – Arial View

1.4 m

Slide 11

EM Pumped Flow Loop for MTOR

•Collection Reservoir

•Electromagnetic Pump

•Storage Reservoir

•Heat Exchangers

•Main

•Bypass

•Coil support plate

•Magnet Coils

Slide 12

LM In @ Q = 0.05 l/s

LM Out

Positive Electrode

NegativeElectrodeFree Surface

Ultrasound Transducer

B

Preliminary Experiments for Inclined Plane Flow with Magnetic Propulsion

Bmax = 0.45 T

L = 45 cm

Slide 13

B = 0, I = 0 B = 0.5 – 0.2, I = 14A

Slide 14

6 7 8 9 10

Time-of-Flight (microsec)

I = 0 A

I = 14 A

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

Ultrasound measurements indicate reduction in flow height

Slide 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

Slide 16

MTOR

Small inclined plane tests

Slide 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)

Slide 18

MHD Tests in NSTX conditions

Flux horns for field concentration (B=0.8 T) and

directional variation

Slide 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

Slide 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.

Slide 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

Water Film flowing under IR heater

Flow direction

Slide 22FLIHY Test Area –

Free surface test section

4 m

Slide 23

FLIHY - Free surface test section

Flow direction~ 8 m/s

Slide 24

FLIHY Free surface test section

Shielded IR heaterFirst Experiments on Free Surface Turbulent Heat Transfer Underway

IR image of water surface emerging from IR heater section

IR study of surface cooling as a function of flow height, velocity

and inclination

Will be summarized by Sergey Smolentsev and Brent Freeze

Slide 25

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

PISCESPlasmaColumn

PISCESPlasmaColumn

Flowing film and stagnant boat tests in PISCES