FLIBE HYDRODYNAMICS SIMULATION FACILITY: DESIGN AND EXPERIMENTAL PLAN

Presented by : Karani Gulec

Contributors : M. Abdou, M. Dagher, B. Freeze, K. Gulec,

N. Morley, S. Smolentsev, A. Ying APEX Project Meeting Argon National Laboratory, Chicago, IL May 10-12, 2000 . FLI-HY EXPERIMENTAL FACILITY GOALS FLI-HY

a Flibe liquid layer as a First-Wall/Blanket in a fusion reactor system. reactor a fusion in a First-Wall/Blanket as layer liquid Flibe a Free-surface temperature is a key feasibility issue for the utilization of utilization for the issue feasibility a key is temperature Free-surface Understand the basic hydraulic phenomena for liquid wall design. wall for liquid phenomena hydraulic basic the Understand

1. heat and flow for Flibe phenomena and science underlying Understand 2. simulant. Flibe using experiments conducting through issues transfer and a guidance to provide results modeling and experimental Compare 3. Flibe. uses that concepts wall for liquid database design that may mechanisms generating flow secondary innovative Utilize 4. characteristics transfer heat the enhance and the hydrodynamics change quickly to ability for their concepts divertor and first-wall liquid of various surface free liquid the renew FLI-HY EXPERIMENTS FOR APEX

Understanding & Modelling the Free Surface Understanding The Basic Hydraulic Heat Transfer using Electrically Low Phenomena For Liquid Wall Design Conducting High Fluid I Demonstration of liquid wall concepts using I Turbulence at and near the free (deformable hydrodynamically scaled experiments and wavy) surface - turbulence intensity and hydrodynamic II Accommodation of penetrations boundary condition - Different penetration size, shape - heat transfer mechanism at the free and positioning surface w/wo heat transfer enhancement - Back wall topology tailoring II MHD effect in free surface flows III Flow recovery system design - on turbulence intensity - flow divertors with minimum - on the turbulent and viscous sub-layers kinematic energy losses. - heat transfer rate penetration

non-wetted back wall

Turbulence structures generated at the liquid- solid interface govern heat transfer and Deflected liquid layer impurity flux at the liquid-plasma interface FLI-HY EXPERIMENTAL FACILITY WILL BE ABLE:

To perform experiments using high Prandtl number Flibe simulant w/o MHD - In hydrodynamics - Liquid layer free surface characterization - Turbulence data measurement - Flow structure characterization - Engineering fluid mechanics

- In scalar transport at the free surface - turbulent heat transfer characterization - turbulent mass transfer characterization

To perform experiments in stages quickly, while upgrading the facility (instrumentation, magnets, protection schemes) for detailed experimental study

- Hydrodynamics - Scalar transport at the free surface - Hydrodynamics with MHD - Scalar transport with MHD - Evaluation of heat transfer enhancement techniques FLI-HY EXPERIMENTAL FACILITY DESIGN

Determining Experimental Facility Operating Parameters

- Scaling Analysis: - determine operating fluid - determine operating hydrodynamic conditions

- Test Section Dimension: - Test Section Length : Turbulent flow development length - Test Section Width : Adequate distance between to eliminate Boundary Layer Effects Developing on the hydrodynamic characteristics of the liquid layer flow - Test Section orientation with respect to direction of gravitational acceleration: fully developed flow and associated operating conditions.

- Experimental Enabling Systems: - Determine experimental liquid layer surface heat transport techniques. - Determine the axial location of the radiant heater and its dimension. - Characterize the heat deposition rate and penetration distance into the liquid accurately to Insure that the uncertainty in the deposited heat is less than the resolution of the temperature measurement. FLI-HY EXPERIMENTAL FACILITY DESIGN - Instrumentation - Determine the Required Measurement Variables, Required Accuracy and Expected Uncertainty. - Determine Measurement Techniques. - Determine and Isolate Errors or Premature Shifts to the Measured Data as a Result of Measurement Techniques. - Feedback to the Facility Design - Instrumentation: - Optical Transparency * Choice of Operating Fluid * Choice of Test Section and Facility Material - Experimental Facility Operating Temperature Window and Sensitivity - Operating Fluid Impurity Content - External Factors - Experimental Facility Upgradeblity. - Material Compatibility when Several Proposed Operating Fluids are used. - Facility Compatibility to the Operating Temperature Window. - Engineering Requirements - Vibration Isolation of the Test Section (Isolation of Discharge Tank from Test Section) - Elimination of Bubble in the Experimental Operating Fluid. - Obtain a Uniform Flow Rate in the Test Section (Nozzle, Flow straightener, Loop Design). - Environmental Protection Systems when KOH is used as an Operating Fluid. HYDRODYNAMIC SIMILARITY CONDITIONS

ρ ρ 2 / 3  µ 1/ 3  µ  For Re and Fr Number Equality U exp Lexp  exp  exp =  ρ base  = ρ base  µ   µ  Ubase  exp base  Lbase  exp base  µ ρ µ 2 U µ σ L   σ exp base exp exp  exp  base base For Re and We Number Equality = µ =   ρ U σ L   σ base exp base base base exp exp

* The effect of back wall curvature on the hydrodynamic characteristics of the flow is taken into account by modifying the using acceleration due to centrifugal force 2 2 U 2 = U → = U = R a = Fr Frc c R gL ach h

Similarity condition for the modified Froude number is geometric, and independent of thermophysical properties of the operating fluid. EXPERIMENTAL HYDRODYNAMIC SIMULATION ANALYSIS Candidate Operation Fluids for Experimental Simulation Study

Cp k el Pr Flibe 2036 0.015 0.193 2380 1.06 155 33.68 2.25 E-07 1 Water 5 C 1000 0.00155 0.073 4200 0.56 10-6 11.55 1.34 E-07 -6 2 Water 25 C 997 0.0009 0.072 4190 0.56 10 6.69 1.36 E-07 3 Water 50 C 988 0.00055 0.068 4180 0.56 10-6 4.07 1.38 E-07 4 KOH 35% wt 5 C 1340 0.0043 0.116 2926 0.68 39.2 18.45 1.75 E-07 5 KOH 43% wt 5 C 1421 0.0075 0.124 2800 0.716 30.1 29.33 1.79 E-07 6 KOH 35% wt, 50C 1330 0.0014 0.112 2926 0.711 96 5.76 1.83 E-07

In selecting Candidate Operating Fluid - optical transparency (use of wide range diagnostic systems) - low operating temperatures (low cost easy operation) - material compatibility - minimum time requirement for experimental facility construction - easy upgradebility are taken into account. Hydrodynamic Scaling of Candidate Fluids for Cliff Operating Fluid SCALING 123 4 5 6 (Re+Fr)

U base/Uexp 1.68 2.01 2.36 1.31 1.12 1.91

L base/Lexp 2.82 4.05 5.6 1.73 1.25 3.66 Note: KOH Case Gives Closer Match to We Number as Well. PHYSICAL MECHANISMS THAT ARE EFFECTED BY THE TEMPERATURE GRADIENT OF THERMOPHYSICAL PROPERTIES OF OPERATING FLUID

Radiative Heat Flux z z z τ surface −shear −stress Radiative Heat Flux Deformable Free Surface x

Magnitude Magnitude µ(T) σ U T Tc Th ∞ ρ(T) H dσ “Renewed” Free Surface σ +∆T × dT µ T > T < µ ρ 2 1 2 1 < ρ µ ρ ρ 2 1 U2 2 2 < ρ ρ 2 1 2 Back Wall ρ 1 µ ρ σ dσ U1 1 1 σ d ∆ × ∆T τ = d dT T H 1 Ma = dT S = dT dT dx µα σ Pr a b gradients on the free surface as a Vortices may form between stratified Layer result of free surface renewal by cold bulk liquid and bulk layer as the eddies impinges on the free surface. a: temperature gradient of density b: temperature gradient of gradient TEMPERATURE GRADIENT OF THERMOPHYSICAL PROPERTIES OF FLIBE SIMULANT SHOULD BE SIMILAR TO FLIBE

50 Flibe 40 (550+DT) C 30 Water 20 (0+D T) C

Pr Number 10 KOH 35 wt % (0+DT) C 0 KOH 43 wt 020406080% (0+DT) C DT

0.25

0.2 Flibe 0.15 (550+DT) C 0.1 Water (0+DT) C 0.05 KOH 35 wt 0 % (0+DT)

Surface Tension (N/m) 0 20406080 DT FLI-HY FACILITY OPERATION PARAMETERS FOR CLIFF CONCEPT WHEN WATER IS USED AS A FLIBE SIMULANT

CLIFF FLI-HY FLI-HY FLIBE WATER WATER 500 oC 5 oC 25 oC Geometric Scale 1 0.35 0.246 Velocity Scale 1 0.595 0.496 Inlet Velocity U (m/s) 10.0 5.95 4.96 Dimensions D (m) .02 0.007 .00492 Dimensions W (m) 1.0 1.0 1.0 Aspect Ratio à ': .02 0.007 0.00492 (W required for same P 1.0 .35 0.246 Radius (m) 3.0 1.05 0.738 Azimuthal flow distance (m) (150o) 7.85 2.74 1.93 Volumetric Flow Rate (m3/s) 0.2 0.0416 0.0244 Strg Tank Size (m3) (30 sec) (1 min) 4 (12) 1.25 (2.5) 0.732 (1.46) Re 35,000 35,000 35,000 We 20,980 4,860 2350

Froude Number Frg 510 510 510

Modified Froude No Frc 150 150 150 Ohnesorge Number (10-3) 5.33 2.18 1.51 Temperature (°C) 500 5 25 Density ρ (kg/m3) 2036 1000 997 µ (kg/m s) 0.015 0.00155 0.0009 Surface Tension σ (N/m) 0.194 0.073 0.072

HEAT TRANSFER EXPERIMENT USING FLIBE SIMULANT WITH MHD - There is no data available on the effect of magnetic field to the hydrodynamic and heat transfer characteristics of turbulent free-surface flow that uses low conducting high Pr number working fluid. - There are only a few studies performed for turbulent flows duct flow cases that use low conducting a high Pr number working fluid. FOR DUCT FLOWS - The heat transfer mechanism in the turbulent flow in the magnetic field does depend on interaction number N. 2 σ HaT 2 > N = = B h Re Recr Re T ρU Nu = (1−1.2× N) Nuo

FOR FREE SURFACE FLOWS - Hydrodynamic characteristics are not the same as duct flows. - MHD suppression effect for free surface turbulent flows that uses low conducting high Pr number working fluid is unknown - MHD effect on the generation/evaluation of the turbulence on the wall (upstream) has not been addressed. FLIBE SIMULANT SELECTION FOR MHD EXPERIMENTS Electrolytes - Some of them have high Pr number. - Some of them may be transparent for diagnostics. - can be handled easier, the cost associated to obtaining and operation may be cheaper. - The thermo-physical properties of electrolytes are dependent to solubility and therefore electrolyte’s operating temperature.

Electrical Conductivity of Several Electrolytes. KOH +H2O may be used as an operating fluid

Electrical Conductivity of KOH + H2O as a function of Viscosity of KOH + H2O as a function of operating temperature and KOH concentration operating temperature MHD EFFECT CONSIDERATIONS

Properties Flibe KOH+Water (35 Working Temperature C 500 50 Density ρ (kg/m3) 2035 1346 Electrical Conductivity σ (1/Ωm) 155 96 Dynamics Viscosity µ(Kg/ms) 0.0148 0.0016

Important Factors for Heat Transfer and MHD Effect Considerations µ Prandtl Number Cp /k 33.2 6.1 Hartman Factor (σ/µ)1/2 101 245 Interaction Factor (σ/ρ) 0.078 0.071

Notes All liquid wall concepts that use Flibe designs are not fully laminarized.

The interaction number indicates the amount of turbulent modification and heat transfer degradation. KOH solution at elevated temperatures has high electrical conductivity for MHD turbulence interaction studies. HEAT TRANSFER EXPERIMENT USING FLIBE SIMULANT WITH MHD

Properties Flibe 35 wt % KOH 35wt % KOH 35wt % KOH

Density ρ (kg/m3) 1980 1330 1340 1340 Electrical Conductivity σ (1/ P 155 96 39.2 30.1 Kinematic Viscosity ν 7.58 x 10-6 1.18 x 10-6 3.2x 10-6 5.59 x 10-6 Hartmann Factor (σ/νρ)½ 101 245 95.6 63.35 Interaction Factor (σ/ρ) 0.078 0.071 0.0292 0.022

Prandl Number cpµ/k 33.7 6.13 18.45 29.3 Working Temperature C 500 50 10 5

Parameters CLiFF w/Flibe KOH+Water

Velocity, U m/s 10 0.57

Depth, D cm 25.5

Magnetic Field, B T 10 1.5

½ Hartmann No, Ha B⋅Dh(σ/νρ) 81 81

Reynold No, Re U⋅Dh/ν 106,000 106,000

2 Interaction No, N σB Dh/ρU 0.062 0.062

Prandl Number cpµ/k 33.7 18.2

Working Temperature C 500 50

DAQ

Sink

On/Off Temp

Vibration Isolating Coupling

Temp Joint

Degasser

Rotatable

Filter

Linear Controller Output Controller Linear

Valve Temp, Fluid Height Fluid Temp, Chiller/Heater On/Off

Flow-meter

P. Actuated P. Fluid In Fluid

Bulk Velocity

Valve

Butterfly Filter Tank E. Actuated E.

Test Section Test Discharge

inlet

T control System T control

Outlet Option Tank Elevated FLI-HY Loop Layout - FLI-HY Loop

Valve

Momentum

Filter

Reservoir Tank Divertor / Dissipater Flow Controlling Flow

r Sink g

Pump FLI-HY FACILITY Current Facility Design Specifications • Switchable water or water/electrolyte working liquid • Discharge or continuos operating modes • 316SS and CPVC components for electrolyte compatibility • >2 m3 working volume • >100 l/s maximum flow rate capability (in discharge mode) • >10 m/s flow velocity • Temperature control from 4 to 50C

FLI-HY EXPERIMENTAL FACILITY

Status

• Design phase is concluding • Construction phase is awaiting design review at UCLA. MeGA-Loop / M-Tor Experiment

Fli-Hy Experiment DIAGNOSTIC SYSTEMS FOR CHARACTERIZATION OF VELOCITY & TEMPERATURE PROFILE, LIQUID LAYER HEIGHT AND SURFACE TOPOLOGY

Flibe simulant is chosen as an optically transparent fluid.

• Flow visualization techniques Using High speed digital camera (1000 frames/sec) - using strobe at varying frequencies to determine surface characteristic structures

- determining temporal and spatial locations of O2 bubbles (with constant generation frequency) in order to determine large scale turbulence structures in the flow. - determination of passive scalar transport in the flow using dye technique.

• Temporal fluid level measurement Using Ultrasonic transducers or Using 5 mW He-Ne laser source, optics and 2-D photo- diode array configurations with high speed data acquisition card - to obtain information about the liquid layer height, surface wave angles at a single point along the flow direction.

• Velocity profile and fluctuation measurements

Using high speed camera and O2 bubbles. Using 2-D Laser Doppler Velocimetry system.

•Temperature profile and fluctuation measurements Using infra-red camera for free surface temperature distribution measurements. Using encapsulated thermo-chromic liquid crystal capsules. SUPPLEMENTARY VU-GRAPHS Energy Equation for Open Channel Flows (2-D, simplified)

∂T ∂T ∂   Pr  ∂T  u + v = α1+ ε   ∂ ∂ ∂  t  ∂ x y y   Prt  y  Where υρ λ Cp εPr = bulk Pr andtl number =

∂T ∂u Pr = local = u'v' T 'v' t ∂y ∂y = = υ υ t ratio of eddy to bulk viscosity t / = = heat transfer coefficient  &p = Cp specific heat at constant pressure ∂ T u 'v ' ∂ y Turbulent Prandtl No: Pr = t ∂ u T 'v ' ∂ y

•Prt Definition: scalar coefficient for local heat transfer, depending on: = u'= x − direction velocity fluctuations T' temperature fluctuations ∂T v'= y − direction velocity fluctuations = temperature gradient in y − direction ∂y ∂u = x − direction velocity component gradient in y − direction ∂y • At free surface, these variables depend on the flow condition (on Re), the surface waviness (on Fr), and back wall topology (turbulence source). • Turbulent intensity /2 is proportional to the fluctuations on

the free surface. Therefore, if turbulent intensity changes, Prt changes, and so does heat transfer at the free surface.