validation of multiphase flow modeling in ansys cfd · cfx model validation ... st dl 05 1.0 1.5...
TRANSCRIPT
Validation of Multiphase Flow Modeling in
ANSYS CFD
Validation of Multiphase Flow Modeling in
ANSYS CFDANSYS CFDANSYS CFD
Th. Frank, C. Lifante, A.D. BurnsHead Funded CFD DevelopmentANSYS GermanyTh F k@
Th. Frank, C. Lifante, A.D. BurnsHead Funded CFD DevelopmentANSYS GermanyTh F k@
© 2009 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary© 2009 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary
[email protected]@ansys.com
Outline
• IntroductionMPF d l lid ti f• MPF model validation for adiabatic air-water flows
• Polydisperse MPF model• Polydisperse MPF model validation – MUSIG model
• Bartolomej testcase (PWR)• Bartolomej testcase (PWR)• Lee testcase (BWR)• Wall boiling with conjugate• Wall boiling with conjugate
heat transfer (CHT)• Summary & Outlook
© 2009 ANSYS, Inc. All rights reserved. 2 ANSYS, Inc. Proprietary
• Summary & OutlookCourtesy by E. Krepper (FZD)
ANSYS as Part of the German CFD Network in Nuclear Reactor Safety
FZ Dresden- ANSYS FZ KarlsruheRossendorf Germany
GRS
Becker Technologies International Guest
AREVA Univ. Applied Sciences
gThAI test facility Visitors
AREVA
TU München:TD N l E
Univ. Applied SciencesZittau-Görlitz: IPM
Univ. Stuttgart: N l E
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TD, Nucl. Energy Nuclear Energy
Methodology of CFD Model Development & Validation
ExperimentExperiment
phys.phys.--math.math.ModelModel
Complex Complex GeometryGeometry
3d CFD Model3d CFD Model Complex Flow Complex Flow ConditionsConditions
ValidationValidationCombination with Combination with other Modelsother Models
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Eulerian MPF Modeling- The Particle ModelMass weighted averaged conservation equations• Mass, momentum, energy transport equations for each phase
1
N
k k k k k klll k
r rt
Ul k
kk k k k k k k k k k kr r r P r
t
U U U F I
secondary drag lift turbulentwall virtual mass
mom. transfer dispersionlubrication
L WL TD Mk D V FF F FI F F
• turbulence models for each phase (e.g. k- / k- SST model, 0-eq. disp. phase turb. Model)
• heat transfer equations for each phase with interfacial transfer closurei t f i l f d i i l l
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• interfacial forces need empirical closure• high void fraction effects, bubble induced turbulence, etc.
Lift force, Wall lubrication force & turbulent dispersion
Lift force:• due to asymmetric wake and deformed asymmetric particle shapeTomiyama CL correlation
( )L G L LL G LrC F U U U (Re ,Re , )L L PC C EoWall lubrication force:• surface tension prevents bubbles from approaching solid wallsAntal, Tomiyama & Frank W.L.F. modelsAntal, Tomiyama & Frank W.L.F. models
T b l t di i f
2
WL G L rel rel W W WwallC r F U U n n n P(Eo, y/d )wall WC C
Turbulent dispersion force:• turbulent dispersion = action of turb. eddies via interphase drag
3 tFD P FC r rU U F FAD model by
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34
tFD P FTD F F P P
P rF P F
C r rU U rd r r
F FAD model by
Burns et al. (ICMF’04)
Bubbly Flow Model Validation FZR MT-Loop and TOPFLOW Database
TOPFLOW
MT Loop
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MT-Loop
CFX Model Validation MT-Loop & TOPFLOW Test Matrix
• M01 experimental test series on MT-Loop• evaluation based on air volume fraction profiles at
L/D=59 2 (z=3 03m) from the sparger systemL/D=59,2 (z=3.03m) from the sparger system• - numerically investigated test case conditions
finely disperse bubbly flow
y J_
L [m
/s]
bubbly flow with near wallvoid fraction maximum
bubbly flow in the transition
wat
er v
eloc
ity regime
bubbly flow with void fraction maximum at pipe center
b bbl flo ith oid
supe
rfici
al bubbly flow with void
fraction maximum at pipe center, bimodal
slug flow
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superficial air velocity J_G [m/s]
Validation: Bubbly FlowsTurbulent Dispersion Forcep
3 00
k-eps + RPI TD (0.5)
3,00
e Fr
actio
n
k-eps + FAD TD
SST + RPI TD (0.5)
SST + FAD TDModel improvement
2,00
. Air
Volu
me
Data
1,00
Nor
m.
0,000 5 10 15 20 25
Radius, mm
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Monodispersed Bubbly Flow MT-Loop Test Case FZR-019
3 5FZD 019
2.5
3.0
3.5
n [-
]Experiment FZR-019
Antal W.L.F., Grid 2
Tomiyama W.L.F., Grid 2
FZD-019:
JL=1.017 m/sJG=0.004 m/s
1.5
2.0
d vo
lum
e fr
actio
y ,
Frank W.L.F., Grid 2
JG 0.004 m/sdP=4.8 mm
Grace dragTomiyama lift
0.5
1.0
norm
aliz
eTomiyama liftT./A./F. Wall L. ForceFAD Turb. Disp.SST turb. modelS t d l
0.00.00 5.00 10.00 15.00 20.00 25.00
Radius [mm]
Sato modelt=0.002s2210 Iterations
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Monodispersed Bubbly Flow MT-Loop Test Case FZR-052
FZD 052 5 5FZD-052:
JL=1.017 m/sJG=0.0151 m/s 4.0
4.5
5.0
5.5n
[-]
Experiment FZR-052
Antal W.L.F., Grid 2
Tomiyama W.L.F., Grid 2JG 0.0151 m/sdP=4.4 mm
Grace dragTomiyama lift
2.5
3.0
3.5
d vo
lum
e fr
actio
n Tomiyama W.L.F., Grid 2
Frank W.L.F., Grid 2
Tomiyama liftT./A./F. Wall L. ForceFAD Turb. Disp.SST turb. modelS t d l 0 5
1.0
1.5
2.0
norm
aliz
ed
Sato modelt=0.002s2400 Iterations
0.0
0.5
0.00 5.00 10.00 15.00 20.00 25.00Radius [mm]
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TOPFLOW Test Facility @ FZDTOPFLOW Test Facility @ FZD
wire-mesh sensormovable diaphragm
movable diaphragm
gas injection
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gas injection
TOPFLOW-074 Test Case Conditions from Test Matrix• Selection of test case conditions:
• TOPFLOW-074 test case was subject of validation in the past• TOPFLOW-074 test case was subject of validation in the past• Superficial velocities: JG=0.0368 m/s
JL=1.017 m/sWi h t t l ti
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• Wire-mesh sensor measurements at locations:z=10, 15, 20, 40, 80, 160, 250, 520mm
3d Bubbly Flow Around ObstacleWater Velocity Comparisony
• ComparisonCFD Experiment
CFD Exp.CFD Experiment
• Absolute water velocity distribution in symmetry plane
• Import of exp. data into CFX Postinto CFX-Post
• Pre-interpolation of exp. data to pz=0.01m
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3d Bubbly Flow Around ObstacleAir Void Fraction Comparison
• ComparisonCFD Experiment
CFD Exp.CFD Experiment
• Air void fraction distribution in symmetry plane
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3d Bubbly Flow Around ObstacleAir Void Fraction Comparison
4) z=40mm 8) z=520mm
7)
8)
3) z=20mm 7) z=250mm
6)
5)
2)
3)
4)
2) z=15mm 6) z=160mm1)
2)
1) z=10mm 5) z=80mm
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3d Bubbly Flow Around ObstacleCross-Sectional Air Void Fraction
5) z=80mm TOPFLOW ExperimentCFX Simulation
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ANSYS CFX Experimental Data Quantitative Comparison
• Quantitative data comparison @ cross sectionsz=±10, ±15, ±20, ±40, ±80, ±160, ±250, ±520mm:z ±10, ±15, ±20, ±40, ±80, ±160, ±250, ±520mm:– absolute water velocity– air volume fraction
z=520mm
x=-35mm x=+35mm
obstacle
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y=0mm z=-520mm
ANSYS CFX Experimental Data Quantitative Comparison
z=-80mmy=0mm
2.0
2.5
actio
n [-]
Experiment (z=-80mm)
CFX Simulation (z=-80mm)y=0mm
1.0
1.5A
ir Vo
lum
e Fr
a
0.0
0.5
-100 -75 -50 -25 0 25 50 75 100
[ ]
Nor
m. A
x [mm]
1.0
1.5
eloc
ity [m
/s]
0.5
olut
e W
ater
Ve
Experiment (z=-80mm)
CFX Simulation (z=-80mm)
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0.0-100 -75 -50 -25 0 25 50 75 100
x [mm]
Abs
o ( )
ANSYS CFX Experimental Data Quantitative Comparison
z=-20mmy=0mm
2.0
2.5
actio
n [-]
Experiment (z=-20mm)
CFX Simulation (z=-20mm)y=0mm
1.0
1.5A
ir Vo
lum
e Fr
a
0.0
0.5
-100 -75 -50 -25 0 25 50 75 100
[ ]
Nor
m. A
x [mm]
1.5
2.0
eloc
ity [m
/s]
0.5
1.0
olut
e W
ater
Ve
Experiment (z=-20mm)
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0.0-100 -75 -50 -25 0 25 50 75 100
x [mm]
Abs
o
CFX Simulation (z=-20mm)
ANSYS CFX Experimental Data Quantitative Comparison
z=20mmy=0mm
2.0
2.5
actio
n [-]
Experiment (z=20mm)
CFX Simulation (z=20mm)
y=0mm
1.0
1.5A
ir Vo
lum
e Fr
a
0.0
0.5
-100 -75 -50 -25 0 25 50 75 100
[ ]
Nor
m. A
x [mm]
1 5
2.0
2.5
eloc
ity [m
/s]
Experiment (z=20mm)
CFX Simulation (z=20mm)
0.5
1.0
1.5
olut
e W
ater
Ve
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0.0-100 -75 -50 -25 0 25 50 75 100
x [mm]
Abs
o
ANSYS CFX Experimental Data Quantitative Comparison
z=80mmy=0mm 2.5
3.0
3.5
actio
n [-]
y=0mm
1.0
1.5
2.0
2.5
Air
Volu
me
Fra
0.0
0.5
0
-100 -75 -50 -25 0 25 50 75 100
[ ]
Nor
m. A Experiment (z=80mm)
CFX Simulation (z=80mm)
x [mm]
1 5
2.0
2.5
eloc
ity [m
/s]
Experiment (z=80mm)
CFX Simulation (z=80mm)
0.5
1.0
1.5
olut
e W
ater
Ve
© 2009 ANSYS, Inc. All rights reserved. 22 ANSYS, Inc. Proprietary
0.0-100 -75 -50 -25 0 25 50 75 100
x [mm]
Abs
o
ANSYS CFX Experimental Data Quantitative Comparison
z=250mmy=0mm
2.0
2.5
actio
n [-]
y=0mm
1.0
1.5A
ir Vo
lum
e Fr
a
0.0
0.5
-100 -75 -50 -25 0 25 50 75 100
[ ]
Nor
m. A Experiment (z=250mm)
CFX Simulation (z=250mm)
x [mm]
1 5
2.0
2.5
eloc
ity [m
/s]
Experiment (z=250mm)
CFX Simulation (z=250mm)
0.5
1.0
1.5
olut
e W
ater
Ve
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0.0-100 -75 -50 -25 0 25 50 75 100
x [mm]
Abs
o
Polydispersed Bubbly Flow Caused by Breakup & Coalescence
Transition from disperse bubbly flow to slug flow:
Balance between:• coalescence of bubbles• turbulent bubble breakup• turbulent bubble breakup
bubble size distribution;l di b bbl flpolydisperse bubbly flow
counter-current radial motion of small and large bubbles;
th l it fi ldmore than one velocity field
new population balance model (i h MUSIG)
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(inhomogeneous MUSIG)
Inhomogeneous MUSIG Model
• momentum equations are solved for N gas phases (vel. groups)• size fraction equations for Mi bubble size classes in each vel. group
bubble coalescence and break up over all M MUSIG groups• bubble coalescence and break-up over all Mi MUSIG groups
N(dP)breakup/
coalescence/evaporation d
1
d3
d4
d5
d6
d7
d8
d2
breakup/conden-sation
v1 v2 v3
Velocity group mass transfer
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dPdP,krit Break up Coalescence
Validation of 3x7 Inhomogeneous MUSIG Model on TOPFLOW-074
• good agreement at levels A, L through R• too fast spreading of the bubble plume from inlet due to too
intensive turbulent dispersionintensive turbulent dispersion
20 0
25.0Exp. FZR-074, level AExp. FZR-074, level CExp. FZR-074, level FE FZR 074 l l I
15.0
20.0
fract
ion
[-]
Exp. FZR-074, level IExp. FZR-074, level LExp. FZR-074, level OExp. FZR-074, level RCFX 074-A, Inlet level (z=0.0m)CFX 074-A, level C
10.0
Air
volu
me
,CFX 074-A, level FCFX 074-A, level ICFX 074-A, level LCFX 074-A, level OCFX 074-A, level R
0.0
5.0
0 0 25 0 50 0 75 0 100 0
A
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0.0 25.0 50.0 75.0 100.0
x [mm]
MUSIG Model Extension
• Basic population balance equations New terms
dn(m, r, t) n(m, r, t) U(m, r, t)n(m, n(m, r, t) m(r, t)dt
r, t)m tt r
B D B D
• Size fraction equations
B B C CB D B D Bubble number density
Breakup/Coalescence terms
B B C C
ji d i i d i i B D B Dj i( r f ) ( r U f ) S S S S
t xS
i ii i 1
i i 1 i 1 i
m mm m m m
Si=
for evaporation
≈≈© 2009 ANSYS, Inc. All rights reserved. 27 ANSYS, Inc. Proprietary
i ii 1 i
i i 1 i 1 i
m mm m m m
Si
for condensation iii
i
ii ≈≈
TOPFLOW Test Facility @ FZD8m
L~ 8
D=195mm
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Courtesy of FZD
Condensation Test Case
• P=2 [MPa]• Jw=1.0 [m/s]• Js=0.54 [m/s]• Ts=214.4 [C]• Tw=210.5 [C] ∆Tw=3.9 [K]• Dinj = 1 [mm]• Detailed experimental data:
– Bubble size distribution– Radial steam volume fraction distribution
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Dirk Lucas, Horst-Michael Prasser: “Steam bubble condensation in sub-cooled water in case of co-current vertical pipe flow”,Nuclear Engineering and Design, Volume 237, Issue 5, March 2007, Pages 497-508
Physical Model Setup
• Standard MUSIG & Extended MUSIG– 25 bubble size classes– 3 velocity groups: y g p
03 [mm],36 [mm], 630 [mm]– Arranged in accordance with critical Tomiyama
bubble diameter for bubble size dependent lift force
– Break up model: Luo & Svendsen (FB=0.025)– Coalescence model: Prince & Blanch (FC=0.05)
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TOPFLOW Condensation Testcase
Inlet BC Inlet Position WLF TD Force Heat Transfer
Config 1 Dinj = 4mm Source point @ Wall - - -
Config 2 Dinj= 4 mm Source point @ 75 mm FWLF CTD=1.5 Nu=2+0.15Rep
0.8Pr0.5
C fi 3 D 1 Source point @ F CTD 1 N 2 0 1 R 0 8P 0 5Config 3 Dinj= 1 mm Source point @ 75 mm FWLF CTD=1.5 Nu=2+0.15Rep
0.8Pr0.5
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Results: Vapor Volume Fraction
© 2009 ANSYS, Inc. All rights reserved. 32 ANSYS, Inc. ProprietaryConfig 2 Config 3Config 1
Results: Vertical Averaged Steam Distribution
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Results: Radial Steam Distribution
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Results: Radial Steam Distribution
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Results: Bubble Size Distribution
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Results: Bubble Size Distribution
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CFD Simulation for Fuel Assemblies in Nuclear Reactors
Material PropertiesMaterial Properties Wall Boiling Wall Boiling & & Bulk CondensationBulk Condensationpp Bulk CondensationBulk Condensation
Conjugate Heat Conjugate Heat Transfer (CHT)Transfer (CHT)TurbulenceTurbulence
Multiphase FlowMultiphase Flow FSI: Stresses &FSI: Stresses &Multiphase Flow Multiphase Flow ModelingModeling
FSI: Stresses & FSI: Stresses & DeformationsDeformations
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Validation againstValidation againstExperimentsExperiments
CFD Simulation for Fuel Assemblies in Nuclear Reactors
Material PropertiesMaterial Properties Wall Boiling Wall Boiling & & Bulk CondensationBulk Condensationpp Bulk CondensationBulk Condensation
Conjugate Heat Conjugate Heat Transfer (CHT)Transfer (CHT)TurbulenceTurbulence
Multiphase FlowMultiphase Flow FSI: Stresses &FSI: Stresses &Multiphase Flow Multiphase Flow ModelingModeling
FSI: Stresses & FSI: Stresses & DeformationsDeformations
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Validation againstValidation againstExperimentsExperiments
Multiphase Flow Regimes for Boiling Water Flowg
subcooled flow
bubbly flow slug flow
annular flow
spray flow
ONB OSB
Tsat
T wall temperature
mean fluid temperature
x
temperature
subcooled nucleate boiling
© 2009 ANSYS, Inc. All rights reserved. 40 ANSYS, Inc. Proprietary
boiling (saturated boiling)
Flows with Subcooled Boiling (DNB) –RPI-Wall Boiling Model
qqqq Mechanistic wall heat partioning model:
EQFWall qqqq
convective heat flux1 ( )F F W Lq A h T T
evaporation heat fluxE G Lq m (h h )
quenching heat flux2 ( )Q Q W Lq A h T T
y
1A 2A2A
uQuenching heat
flux
Convective heat
flux
© 2009 ANSYS, Inc. All rights reserved. 41 ANSYS, Inc. Proprietary
t*m *m *m
RPI-Wall Boiling Model –Submodels for Model Closure
Submodels for closure of RPI wall boiling model:– Nucleation site density: Lemmert & Chawla , User Defined– Bubble departure diameter:
Tolubinski & Kostanchuk, Unal, Fritz, User Defined– Bubble detachment frequency:q y
Terminal rise velocity over Departure Diameter, User Defined– Bubble waiting time:
Proportional to Detachment Period, User Definedp– Quenching heat transfer: Del Valle & Kenning, User Defined– Turbulent Wall Function for liquid convective heat transfer coefficient
• Correlation for bulk flow mean bubble diameter required:• Correlation for bulk flow mean bubble diameter required: e.g. Kurul & Podowski correlation via CCL
• Supported combination of wall boiling & CHT in the solid
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pp g– GGI & 1:1 solid-fluid interfaces
RPI Wall Boiling Model in the ANSYS CFX-Pre 12.0 GUI
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The Bartolomej et al. The Bartolomej et al. The Bartolomej et al. Testcase (1967,1982)The Bartolomej et al. Testcase (1967,1982)
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The Bartolomej Test Case
R = 7.7 mm
Variable Value
P 4.5MPa
R 7.7 mm
2 m
57M
W/m
2
Gin 900 kg/(s m2)
0.57MW/m2 q
Z= 2
q=0.
5
Subcooling 58.2 K
q
© 2009 ANSYS, Inc. All rights reserved. 45 ANSYS, Inc. ProprietaryGin=900 kg/(s m2)
Multiphase Flow Model
• Steam-Water 2-phase flow:W t ti h– Water: continuous phase
– Water Steam: disperse bubbles (particle model)
• Material properties (EOS):Material properties (EOS):– IAPWS-IF97 water - water steam property tables
• Modified law for interfacial area– Kurul & Podowski type bulk bubble diameter: dB=f(Tsub)– Accounting for higher volume fraction of the steam phase
Turbulence Model• Turbulence Model– SST turbulence model for continuous phase– 0-eq. disperse phase turb. model + Sato bubble induced turbulence
© 2009 ANSYS, Inc. All rights reserved. 46 ANSYS, Inc. Proprietary
q p p
Inter-Phase Mass, Momentum and Energy Transfergy
• Mass transfer modelTh l Ph Ch M d l (b lk b ili / d ti d l)– Thermal Phase Change Model (bulk boiling/condensation model)
– RPI wall boiling model
• Momentum transfer modelsMomentum transfer models– Grace drag– FAD turbulent dispersion force
T i lift f– Tomiyama lift force– Wall lubrication force (none, Antal, Tomiyama)
• Heat transfer modelsHeat transfer models– Water: Thermal Energy– Water Steam: Saturation temperature
T i t d l
© 2009 ANSYS, Inc. All rights reserved. 47 ANSYS, Inc. Proprietary
– Two resistance model– Ranz Marshall correlation for bubble heat transfer
Numerical Grids
• Validation on mesh hierarchy with regular refinement factor of 4 (2d meshes)
Grid Grid1 Grid2 Grid3
refinement factor of 4 (2d meshes)
Grid Grid1 Grid2 Grid3
# Nodes20 150 40 300 80 600
(uniform)20x150 40x300 80x600
Max y+ 264 133 69Max y 264 133 69
Δt [s] 10-2 10-3 5x10-4
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[ ]
Grid1
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Grid 2
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Grid 3
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Comparison to Experimental Data
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Comparison to Experimental Data- Parameter & Model Variation
Influence of wall heat flux: Influence of wall lubrication force model:
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The Lee et al. Testcase The Lee et al. Testcase The Lee et al. Testcase (ICONE-16, 2008)
The Lee et al. Testcase (ICONE-16, 2008)
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Lee et al. (2008) Testcase
• Axially symmetric circular annulus
Radial dimensionsOutlet
RC
RR0
Measuring
r
• Radial dimensions– Inner radius of outer tube: R = 18.75 mm– Outer radius of inner tube: R0 = 9.5 mm– Core radius: RC = 3/4 R0
gPlane(for experimentaland numericalResults)
Core radius: RC 3/4 R0
– Annulus width: 9.25 mm
• Axial dimensionsT t l h ti ti h i ht L 1670
Adiabatic WallHeated Wall
– Total heating section height: LT = 1670 mm– Distance between inlet and measuring plane:
LM = 1610 mm
R di l P iti R
LM LT
• Radial Position: RP– Dimensionless, radial distance from inner tube
(RP = 0) to outer tube (RP = 1) across the annulus:
Annulus
Inner Tube(Heating Rod) z
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Inlet
0
0
RRRrRP
Outer Tube
Annulus
Axis
Geometry and Mesh
Geometry & Mesh generation: Figure 4: Generated one layer mesh
Figure 1: 25° segment of the geometry
Annulus
CoreShell
Figure 2: 1° simulated segment of the geometry
Figure 3: 1° segment with one-layer mesh example
symmetrysymmetry
© 2009 ANSYS, Inc. All rights reserved. 56 ANSYS, Inc. Proprietary
symmetrysymmetry
Mesh Hierarchy
Mesh Name Grid 01(coarse)
Grid 02(medium)
Grid 03(fine)
Domains ( 1 = HFO, 2 = CHT ) * 1 2 1 2 1 2
No of Nodes 1: 6342 1: 24682 1: 97362No. of Nodes 1: 63422: 12684
1: 246822: 49364
1: 973622: 194724
No of Elements 1: 20x150 1: 40x300 1: 80x600No. of Elements(hexahedra) 2: 40x150 2: 80x300 2: 160x600
y+max
Set16 ~84 ~41 ~24y max(at 1st node near wall)
Set25 ~88 ~45 ~25
Tstep Δt [s] Set16 0.001 0.002 0.0002
© 2009 ANSYS, Inc. All rights reserved. 57 ANSYS, Inc. Proprietary
Tstep Δt [s] Set16 0.001 0.002 0.0002
Set25 0.1 0.0125 0.0002
Selection of Extreme/Limiting Testcase Conditions
• Concentrating on 2 (out of 12) datasets:
Set 25(least of all steam)
Set 16(most of all steam)
• Parameter comparisonSet No.* q’’ [kW m^-2] G [kg m^-2s] Tin [°C] Pin [kPa]
16 320.4 718.8 83.8 121.1
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25 220.0 1057.2 90.1 134.4
Required Parameter Modifications in Comparison to PWR Conditions
Found that submodels need modifications for BWR conditionsconditions (see also Tu&Yeoh, Anglart et al., Krepper, Koncar):
1. Bulk bubble diameter (BBD)Kurul & Podowski dB,max~1.5mm @ wallmodified d law d ~4 0mm @ wallmodified dB law dB,max~4.0mm @ wall
2. Bubble departure diameter (BDD)Tolubinski & Kostanchuk dW ~0.5mm max.const. bubble dept. diam. dW =1mm - 3mm
3. A2 - Wall area fraction influenced by steam bubblesdefault 0 5
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default 0.5increased up to 2.0
BBD & BDD Modifications Test Matrix Overview• Trying to systematically increase Bubble Departure
Diameter to investigate its influence on Heat Flux to V (Q ) filVapor (QV) profile
→ Test series with increasing BDD starting from dW.max ≈ 0.5 mm→ 1 mm; 2 mm; 3 mm; ;→ T&K * 4.0
BDD BDD User definedTolubinsky & Kostanchuk dW [mm]
K&P yes -
bbdmod01 - 1 = const.
bbdmod02 - 2 = const.
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bbdmod02 2 const.
bbdmod03 - 3 = const.
BBD Modification / Set 25: Gas Volume Fraction @ z = 1610 [mm]
Set25 : Bulk Diameter Modification Comparison: Gas Volume Fraction (rG)
0.25
0.30
Gas Volume Fraction (rG)
0 10
0.15
0.20
r G[ ]
0.00
0.05
0.10
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Radial Position (Rp) [ ]
G3 K&P G3 dbmod01 G3 dbmod02
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G3_K&P G3_dbmod01 G3_dbmod02
G3_dbmod03 Experimental Data
BDD Modification / Set 25:Gas Volume Fraction @ z = 1610 [mm]
Set25 Bubble Departure Diameter Modification Comparison: Gas Volume Fraction (r )
0.30
0.35
Gas Volume Fraction (rG)
0.15
0.20
0.25
r G[ ]
0.00
0.05
0.10
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Radial Position (Rp) [ ]
G3 K&P G3 dbmod02 bddmod01 G3 dbmod02 bddmod02
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G3_K&P G3_dbmod02_bddmod01 G3_dbmod02_bddmod02
G3_dbmod02_bddmod03 Experimental Data
A2F Limiter Modification: Results Set 25,Gas Volume Fraction @ z=1610[mm]
Set25 A2F Mod Comparison: Gas Volume Fraction (rG)
0 350,400,45
0 150,200,250,300,35
r G [
]
0,000,050,100,15
0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 10 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Radial Position (Rp) [ ]G3_K&P G3_dbmod02_bddmod01_A2F02
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G3_dbmod02_bddmod02_A2F02 G3_dbmod02_bddmod03_A2F02Experimental Data
Grid Independency: Results Set 25, Gas Volume Fraction @ z = 1610 [mm]
Set25 New Grid Comparison: Gas Volume Fraction (rG)Gas Volume Fraction (rG)
0 300,350,40
0,150,200,250,30
r G [
]
0,000,050,10
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1Radial Position (Rp) [ ]
G1_dbmod02_bddmod02_A2F02 G2_dbmod02_bddmod02_A2F02
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G3_dbmod02_bddmod02_A2F02 G4_dbmod02_bddmod02_A2F02Experimental Data
The Lee et al. Testcase The Lee et al. Testcase The Lee et al. Testcase (ICONE-16, 2008)- Conjugate Heat
T f
The Lee et al. Testcase (ICONE-16, 2008)- Conjugate Heat
T f Transfer -Transfer -
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Heat Source in Solid Material & Conjugate Heat Transfer Prediction
HFO (Heat Flux Only): Fluid Domain (Annulus) → area specific heat flux boundary condition #
Fluid Domain
Outlet
Inlet
CHT (Conjugated Heat Transfer): Fluid Domain (Annulus) + Solid Domain (Non-Heated Rod Shell) + + Solid Domain (Heated Rod Core) → volume specific heat source #
Fluid Domain
Outlet
SolidD iSolid Domain #
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InletDomainSolid Domain #
The RPI Wall Boiling Model:Lee et al. Testcase with CHT
• Specific energy source in solid material, Set25(equiv. to qWall):
ECore=8.23107 [W/m3]
• Temperature and Steam VF distribution indistribution in vertical plane
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The RPI Wall Boiling Model:Lee et al. Testcase with CHTSet25 & CHT: Water temperature monitors xW=1.5mm, z=83.5mm,
TL|OutletTL|z=835mm
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Iterations Iterations
TL|Intlet
The RPI Wall Boiling Model:Lee et al. Testcase with CHT
Set25 & CHT: Grid independence for temperature distribution @ z=1610[mm]distribution @ z=1610[mm]
Heated Core Fluid Domain
Unheated “Cladding”
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The RPI Wall Boiling Model:Lee et al. Testcase with CHT
Set25 & CHT: Vapour VF distribution @ z=1610[mm]
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New R&D Consortium
ANSYS Germany
R&D Initiative:“Modeling Simulation & Germany
TUD, Dept. Fluid
Mechanics
Karlsruhe Inst. of
Technology (KIT)
Modeling, Simulation & Experiments for Boiling Processes in Fuel Assemblies of PWR”
FZ Dresden/ TUD, Dept.TUM, Dept.
Th
Assemblies of PWR
Dresden/Rossen-
dorf
TUD, Dept. Nucl. Eng.Thermo-
dynamics
TUD Medical Faculty
Univ. Appl.
Univ.Bochum,
Dept. Energy
Systems
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Univ. Appl. Sciences
Zittau/ Görlitz
Modeling, Simulation & Experiments for Boiling Processes in Fuel Assemblies of PWR
• Ultrafast electron beam X-ray CT of fuel rod bundle in titanium pipe on TOPFLOW @ FZD:
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Images by courtesy of U. Hampel, FZD
Modeling, Simulation & Experiments for Boiling Processes in Fuel Assemblies of PWR
Wall boiling simulation insimulation in a 3x3 rod bundle with
idspacer grid:
WallWall superheat TW-TSat
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Summary & Outlook
• Overview on ANSYS CFD multiphase flow model development and validation
• Continuous effort in model improvement, R&D• Emphasis in validation on BPG, comparison to
data, geometry & grid independent modeling• High interoperability of physical models
O tl k• Outlook:– Ongoing & customer driven CFD model development– Research cooperation with Industry & AcademiaResearch cooperation with Industry & Academia– More & more complex MPF phenomena– Coupling of wall boiling model to inhomogeneous MUSIG
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p g g g– Extension of the wall heat partitioning in wall boiling model
Th k Y !Thank You!© 2009 ANSYS, Inc. All rights reserved. 75 ANSYS, Inc. Proprietary