wp2.1: pressurized thermal shock - nurisp.eu package 2.1: pressurized thermal shock (pts) main...

WP2.1: Pressurized Thermal Shock

D. Lucas, P. Apanasevich, B. Niceno, C. Heib, P. Coste, M. Boucker, C. Raynauld,J. Lakehal, I. Tiselj, M. Scheuerer, D. Bestion

Work package 2.1: Pressurized Thermal Shock (PTS)

• Introduction (D. Lucas)• Improved model approaches (P. Coste)• Benchmark simulations on TOPFLOW-PTS (P. Apanasevich)• Conclusions and recommendations (D. Lucas)

NURISP SECOND OPEN SEMINARApril 2-3, 2012, Karlsruhe

Final question: Thermal loads on the RPV wall?

2


Main achievements of the WP

• Improvement of model approaches for:– Turbulence models– Interfacial heat transfer models– 1D code WAHA for condensation induced water hammer

hot steam inlet

closed end

SLUG

slug head

The condensation induced water hammerexperiment by Martin et al. was simulated withthe WAHA code


• Test of capabilities of CFD-codes for PTS– Benchmark on TOPFLOW-PTS experiments– Benchmark on COSI experiments– Validation on ROSA experiments

• RecommendationsROSA at Large Scale Test Facility

3


Presentations

• Introduction (D. Lucas)

• Improved model approaches (P. Coste)


• Benchmark simulations on TOPFLOW-PTS (P. Apanasevich)

• Conclusions and recommendations (D. Lucas)

4

Improved model approaches

TransAT ANSYS CFX 12.0 NEPTUNE_CFD

Formulation One-fluid Two-fluid Two-fluid

Turbulence (includingbuoyancy)

One-fluid k-ε(URANS or V-LES)

Shear Stress Transport (SST): combination of k-ε and k-ω)

Two-fluid k-ε(URANS or V-LES)

Wall Wall functions Wall functions Wall functions

Large interface

Level set AIAD detection based on the gas volume fraction αG

Interface recognition based on ∇αG

w/o reconstruction

Int. mom. transfer

Turbulent viscosity from one-fluid k-ε

Free surface drag Anisotropic friction

Mass transfer model

Scale Adaptative Interfacial transfer model

Hughes and Duffey Large Interface Model for condensation



5

V-LES as tested in NURISP COSI calculations

• URANS (k-εεεε) calculation with two modifications

• A decrease of the turbulent viscosity based on the comparison between a constant filter scale ∆ input by the user and the integral length scale output from the k-ε equations (Johansen et al., 2004)

εεν µ

²;1min

233

k

kCCT

∆=εν µ

²kCT =

Turbulence


• A consistent modification of the turbulent Reynolds number used in the closure laws

εk ε

( )∆= ,min LLt

Φ

−=

)(

)_(23

TransATsetlevel

or

CFDNEPTUNEphaseTwok

L

ε

21kut =


6

AIAD free surface drag CFX 12.0

•Algebraic Interfacial Area Density framework (Egorov, 2004; Deendarlianto et al., 2012)

( ) 2D D Mix L GF C A U Uρ= −Drag force:

1=Gα

0=Gα

1=Gα

0=Gα

D,D DC ; A

D,FS FSC ; A

D,B BC ; AB

GB d

Aα6=

D

LD d

Aα6=

FS GA α= ∇

Mix G G L Lρ ρ α ρ α= +

Int. mom. transfer


Bd

D B D,B FS D,FS D D,DC f C f C f C= + +Drag coefficient: f: blending functions

•Free surface drag coefficient (Höhne, 2009) [ ]2

2 G G L LD

Mix slip

CU

α τ α τρ

+=

2 2 2L,G L,G L,G

y,L,Gx,L,G z,L,GL,G L,G

FS FS FS

uu ux y z

x A y A z A

α α α

τ µ

∂ ∂ ∂ ∂∂ ∂∂ ∂ ∂ = ⋅ + ⋅ + ⋅ ∂ ∂ ∂


7

Anisotropic free surface friction NEPTUNE_CFD

Normal surface direction: bubbles and droplets drags

Tangent plane : waves taken into account in roughness wall laws on liquid and gas sides

Int. mom. transfer

( )qk

LItrLIqk

nrqk

qkq uFuFJ ,,,

rrr−−=′ → α


2*2*LLGG uu ρρ =

+= t

GG r

g

uyr

2*

12 ,min ββ

•Modelling of waves that can not be simulated

•Wind contribution (Charnock)

•Liquid turbulence contribution


8

Scale Adaptative Interfacial transfer Model TransAT

Mass transfer

Interphase mass transfer term in Level Set topology equation : D / Dt Kφ φ= ∇

K m / ρ= &-> phase change velocity (m/s):

.

/ / . .Pr . Re Ren mt t t tK u m u C fρ ≡ =

Extension of the Surface Divergence approach :


t t t t

• Banerjee et al. (2004): m=-1/2 with a turbulent Reynolds number taken in the core flow of the turbulence-generating phase

• TransAT (Lakehal and Labois, 2011): m=-1/4 with a turbulent Reynolds number taken right at the interface

validated on the NURISP calculations of three Lim et al. (1984) tests


9

Two-phase CFD models CFX 12.0 and NEPTUNE_CFD

Mass transfer

Mass transfer term deduced from a heat balance at the interface

• CFX 12.0 TOPFLOW-PTS calculations: infinite

Condensation mainly controlled by the liquid side

( ) ( )12

1 HH

TThTTh GsatgeLsatle

−−+−

=Γ

geh

Gas side model (hge)


• NEPTUNE_CFD 1.0.8: Jayalilleke (1969) wall law

• CFX 12.0 TOPFLOW-PTS calculations: Hughes and Duffey model

Liquid side model (hle)

• NEPTUNE_CFD 1.0.8: large interface model ✦

4121

,2

=νερ

π LLpLle aCh


10

Large Interface Model for hle NEPTUNE_CFD

Mass transfer

Two free surface regimes : smooth and wavy

geh

Characterized by the liquid turbulence, from L-q diagram from Brochini and Peregrine, JFM 2001


A wall function-like model for hlein large interface regions


11

Bench: Steam Water STratified flow NEPTUNE_CFD and TransAT

geh

x

z

Outlet

0

1260 cm

10 cm

910 cm

MeasurementsInlet

Gas

Liquid

Wall

Wall

Case Freesurface (kg/s) (kg/s) (°°°°C) (m2.s-2) (m2.s-2) (m2.s-3) (m2.s-3)

•Co-current condensing flow•Rectangular channel •z dim: 30.5 cm

Lim et al. (1984) experiment

Lm& Gm& GT Lk Gk Lε Gε


1 Smooth 0.657 0.041 111 2.8 10-4 0.36 3.9 10-4 6.1

2 Smooth/wavy 0.657 0.065 116 2.8 10-4 0.92 3.9 10-4 24

6 Wavy 1.44 0.065 116 1.3 10-3 0.92 4.1 10-3 24

8 Wavy 1.44 0.126 125 1.3 10-3 3.4 4.1 10-3 180

•TransAT 32x130•NEPTUNE_CFD 18x410, 36x820, 72x1640

CFD meshes: 2D

turbulence: URANS


12

Bench: Steam Water STratified flow (cont.)geh

Smooth Transitional Wavy

TransAT URANS


Smooth Transitional Wavy

NEPTUNE_CFD1.0.8

•URANS •default LIM

optionssmall Ret y+ from 5 (m8) to 20 (m2)


13

Benchmarking on COSI 3.8 NEPTUNE_CFD and TransAT

geh

Vapor inlet(co-current runs)

Outlet

ECC liquid inlet

« Upstream »

« Downstream »

COSI 3.8: a test w/o weir

COSI: thermohydraulics conditions of a PWR PTS, scale: 1/100 volume


Cold water (ECC)

Cold leg

Vapor inlet(co-current runs)

Weir

Downcomer

Downcomer


14

COSI 3.8: sensitivity to the mesh NEPTUNE_CFD

geh

G1

G0 S1 A1S0

S1 G1 S2 A2

MeshNb of cells

Гp/Гt,exp

G0S0A01.58 105

0.928

G0S1A16.40 105

0.931

G1S2A2 0.918


S2

S3

G1S2A22.21 105

0.918

G1S3A2 0.928

G1S3A35.43 105

0.931


15

COSI 3.8: TransAT meshgeh

Cartesian grid


Cross section:37x37 cells


16

COSI 3.8: URANS or V-LES NEPTUNE_CFD and TransAT

geh

12

3

4

x= -0.05 x= -0.3 x= -0.885x= -0.21N

orm

aliz

ed h

eigh

t

12 3

4

TransAT


Nor

mal

ized

hei

ght

0,4 0,6 0,8 1

00,

20,

40,

60,

8N

orm

aliz

ed h

eigh

t

0,4 0,6 0,8 1

00,

20,

40,

60,

8expNCFD VLESNCFD URANS

0,4 0,6 0,8 1

00,

20,

40,

60,

8

0,4 0,6 0,8 1

00,

20,

40,

60,

8

12

3

4

x= -0.05 x= -0.3 x= -0.885

x= -0.21

Nor

mal

ized

hei

ght

NEPTUNE_CFD1.0.8


17

COSI 3.8: URANS or V-LES (cont.) NEPTUNE_CFD and TransAT

geh

5 6 7 8

8 567

x= +0.52 x= +0.37 x= +0.145 x= +0.065 N

orm

aliz

ed h

eigh

t

TransAT


Nor

mal

ized

hei

ght

0,4 0,6 0,8 1Normalized temperature

00,

20,

40,

6N

orm

aliz

ed h

eigh

t


00,

20,

40,

6


00,

20,

40,

6


00,

20,

40,

6

8 567

x= +0.52 x= +0.37 x= +0.145 x= +0.065

Nor

mal

ized

hei

ght

NEPTUNE_CFD1.0.8


18

COSI 3.8: TransAT and NEPTUNE_CFDgeh



19

COSI 3.8: TransAT and NEPTUNE_CFD (cont.)geh



20


Presentations




• Benchmark simulations on TOPFLOW-PTS experiments (P. Apanasevich)


21

TOPFLOW-PTS Experiments

Pressure Vessel

TOPFLOW-PTS facility

IR cameraThermo lances

High-speed camera

WMS

Cold leg (CL)

Pump simulator (PS) Downcomer

Reference plant:• EDF CPY 900 MWe PWR• Scale 1:2.5• Air-water tests � without condensation• Steam-water tests � with condensation

TOPFLOW-PTS facility


22

Numerical Grids

Neptune_CFD:• IRSN-EDF grid• 594,000 cells• 1,500,000 cells

ANSYS FLUENT:• HZDR grid• 865,000 cells

ANSYS CFX:• HZDR grid• 1,450,000 cells


23

CFD Codes

• Neptune_CFD 1.0.8 (IRSN, CEA):– Air-water test � IRSN– Steam-water test � CEA– Two-fluid model – Turbulence: k-ε model (for each phase) – Large Interface Method (LIM)– Transient

• CFX 12.0 (HZDR):• CFX 12.0 (HZDR):– Two-fluid model– Turbulence: SST (for each phase)– Algebraic Interfacial Area Density Model (AIAD)– Steady state/transient

• FLUENT 12.0 (PSI):– One momentum equation & Volume Of Fluid (VOF) approach – Turbulence: LES approach (Smagorinsky model)– Transient


24

SimulationsSimulations ofof Air Air –– WaterWater ReferenceReference CaseCase


25

Boundary Conditions

� Water level in the cold leg: 50%� MECC, Re_ECC=62700, θECC=0

� MPS_in, Re_PS=42200, θPS=1� MECC/MPS_in=1.7� MDC=MECC + MPS_in (out)� θAir=0.4

HZDR IRSN PSI


26

ECC Jet Behaviour

� ANSYS CFX � Neptune_CFD� ANSYS FLUENT � Exp., HS camera

HZDR IRSN PSI


27

Cold Leg: Water Temperature

0.0

0.1

0.2

0.3

0.4

0.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

η, [

-]

θ, [-]

LA1 Temperature Profiles Upstream from ECC injection

CFXNCFDFLUENTExperimentMeasurement error

0.0

0.1

0.2

0.3

0.4

0.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

η, [

-]

θ, [-]



LA2

LA4

LA3

LA1θ, [-] θ, [-]

0.0

0.1

0.2

0.3

0.4

0.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

η, [

-]

θ, [-]



0.0

0.1

0.2

0.3

0.4

0.5

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

η, [

-]

θ, [-]


CFX

NCFD

FLUENT

Experiment

Measurement error

HZDR, IRSN, PSI


28

Cold Leg: Bottom Wall Temperature� ANSYS FLUENT � Neptune_CFD

1

0.8

0.6

0.4

0.2

0

� ANSYS CFX

� ExperimentIR camera


29

Downcomer

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

-0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

θ, [

-]

ζ, [-]

DCLA3 Temperature Profiles


0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

-0.05 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35

θ, [

-]

ζ, [-]



DCLA1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.05 0.10 0.15 0.20 0.25 0.30 0.35

θ, [

-]

ζ, [-]



0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.05 0.10 0.15 0.20 0.25 0.30 0.35

θ, [

-]

ζ, [-]



ζ, [-]ζ, [-]DCLA1

DCLA3

DCLA17

DCLA20

HZDR, IRSN, PSI


30

SimulationsSimulations ofof SteamSteam –– WaterWater ReferenceReference CaseCase



31

Boundary Conditions

ECCPS_in

DC_out

Steam_out

PS_out

Steam_in

DC

PS

ECCPS_in

DC_out

Steam_out

PS_out

Steam_in

DC

PS

Experiment

� Water level in the cold leg: 50%� MECC, Re_ECC=325,000, θECC=0

� MPS_in, Re_PS=234,000, θPS_in=1� MECC/MPS_in=1.7� MDC=MECC + MCond (out)� MPS_out=MPS_in

� θSteam=1

HZDR PSI CEA


32

Modeling of Direct Contact Condensation

• Neptune_CFD 1.0.8 (CEA):– Coste and Laviéville (2009)

� for smooth flows (Lakehal et al. 2008)

� for wavy flows

121 1 3 432 2 40 35 0 3 2 83 2 14t t t

t

K. Pr Re . . Re . Re

u

− − = −

1182

tt

KPr Re

u

−−=

• FLUENT 12.0 (PSI):– Hughes and Duffey (1991)

• CFX 12.0 (HZDR):– Hughes and Duffey (1991)

1 12 42

tt

KPr Re

u π− −

=

1 12 42

tt

KPr Re

u π− −

=


33

Cold Leg

LA2

LA4

LA30

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.50 0.60 0.70 0.80 0.90 1.00

η, [

-]

θ, [-]

LA1 Temperature profile Upstream from ECC injection

CFX_refinedNCFD_coarseNCFD_refinedFLUENT_coarse

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.5 0.6 0.7 0.8 0.9 1.0

η, [

-]

θ, [-]

LA2 Temperature profile Downstream from ECC injection


LA1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.5 0.6 0.7 0.8 0.9 1.0

η, [

-]

θ, [-]



0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.5 0.6 0.7 0.8 0.9 1.0

η, [

-]

θ, [-]



HZDR PSI CEA


34

Cold Leg

θ=0.875

Neptune_CFD ANSYS CFXANSYS FLUENT

1FluentFluent

Fluent

ΓΓ = =Γ

% 1.73CFXCFX

Fluent

ΓΓ = =Γ

%2.25NCFDNCFD

Fluent

ΓΓ = =Γ

%


35

Downcomer

HZDR PSI CEA

Neptune_CFD (refined grid):• Homogeneous temperature• Homogeneous temperature• θmin=0.936• θmax=0.946• ∆θ=0.01

ANSYS CFX:• Inhomogeneous temperature• Cold water plume• θmin=0.638• θmax=0.791• ∆θ=0.153 ANSYS FLUENT:

• Homogeneous temperature• θmin=0.881• θmax=0.962• ∆θ=0.081


36


Presentations




• Benchmark simulations on TOPFLOW-PTS (P. Apanasevich)


37


Conclusions and Recommendations• Clear benefits of a multi-scale analysis of thermal-hydraulic issues:

– condensation induced water hammer investigated by CFD (NURESIM) and 1D WAHA code

– coupled system code – CFD simulation for ROSA

• Clear progress for two-phase PTS simulations with CFD– NEPTUNE_CFD with URANS-LIM and TransAT with LEIS could simulate COSI test

and several tests of Lim et al. including smooth interface and wavy interface– but: pre-test simulation of steam-water TOPFLOW-PTS experiments showed clear


– but: pre-test simulation of steam-water TOPFLOW-PTS experiments showed clear deviations between the results obtained by different codes and models(no results with TransAT, since the data are proprietary and thus not shared with ASCOMP)

Conclusions and Recommendations• Further investigations are necessary to explain and minimize the inconsis-

tencies between the codes and to identify the best models � post test simulations on TOPFLOW-PTS steam-water experiments (now available)

• Turbulence modeling of interfacial turbulent flows should be further improved and validated for flows with wavy interface and condensation.

38


Conclusions and Recommendations (cont.)• The modeling of interfacial friction in case of the two-fluid URANS approach

should be further improved – especially for waves smaller than the grid size.• Dedicated experimental data or DNS is needed to consider the influence of

heat and mass transfer on friction and turbulence.• Direct contact condensation approaches in TransAT (LEIS) and

NEPTUNE_CFD (URANS with LIM) seem to be applicable for PTS, but validation against TOPFLOW-PTS steam-water experiments should be


validation against TOPFLOW-PTS steam-water experiments should be done as a next step.

• Benchmarking of different codes and models should be done since it provides valuable information on the strengths and weaknesses of the single approaches.

• Before reactor application for PTS simulation, it is recommended to validate a frozen version of a modelling approach at least on the following validation base: air-water Fabre et al. data, Lim et al. (1984), jet impingement data (Bonetto and Lahey, Iguchi experiments) and COSI tests. TOPFLOW-PTS and ROSA experiments should be added in the future.

39

wp2.1: pressurized thermal shock - nurisp.eu package 2.1: pressurized thermal shock (pts) main...

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