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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
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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)
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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
© 2009 ANSYS, Inc. All rights reserved. 3 ANSYS, Inc. Proprietary
TD, Nucl. Energy Nuclear Energy
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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
© 2009 ANSYS, Inc. All rights reserved. 5 ANSYS, Inc. Proprietary
• interfacial forces need empirical closure• high void fraction effects, bubble induced turbulence, etc.
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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
© 2009 ANSYS, Inc. All rights reserved. 6 ANSYS, Inc. Proprietary
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)
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Bubbly Flow Model Validation FZR MT-Loop and TOPFLOW Database
TOPFLOW
MT Loop
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MT-Loop
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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
© 2009 ANSYS, Inc. All rights reserved. 8 ANSYS, Inc. Proprietary
superficial air velocity J_G [m/s]
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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
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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
© 2009 ANSYS, Inc. All rights reserved. 13 ANSYS, Inc. Proprietary
• Wire-mesh sensor measurements at locations:z=10, 15, 20, 40, 80, 160, 250, 520mm
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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
© 2009 ANSYS, Inc. All rights reserved. 16 ANSYS, Inc. Proprietary
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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
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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 ( )
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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)
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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
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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
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0.0-100 -75 -50 -25 0 25 50 75 100
x [mm]
Abs
o
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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
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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)
© 2009 ANSYS, Inc. All rights reserved. 24 ANSYS, Inc. Proprietary
(inhomogeneous MUSIG)
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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
© 2009 ANSYS, Inc. All rights reserved. 25 ANSYS, Inc. Proprietary
dPdP,krit Break up Coalescence
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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
© 2009 ANSYS, Inc. All rights reserved. 26 ANSYS, Inc. Proprietary
0.0 25.0 50.0 75.0 100.0
x [mm]
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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 ≈≈
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TOPFLOW Test Facility @ FZD8m
L~ 8
D=195mm
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Courtesy of FZD
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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
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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
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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
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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
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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
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boiling (saturated boiling)
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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
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t*m *m *m
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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
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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
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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
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q p p
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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
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– Two resistance model– Ranz Marshall correlation for bubble heat transfer
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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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[ ]
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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
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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
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symmetrysymmetry
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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
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Tstep Δt [s] Set16 0.001 0.002 0.0002
Set25 0.1 0.0125 0.0002
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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
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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
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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.
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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
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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
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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
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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
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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 #
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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
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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
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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
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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
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Th k Y !Thank You!© 2009 ANSYS, Inc. All rights reserved. 75 ANSYS, Inc. Proprietary