spray model validation on single droplet heat and mass transfers for containment applications –...
TRANSCRIPT
SPRAY MODEL VALIDATION ON SINGLE DROPLET
HEAT AND MASS TRANSFERS FOR CONTAINMENT
APPLICATIONS – SARNET-2 BENCHMARK
J. Malet1, T. Gelain1, S. Mimouni2, G. Manzini3, S. Arndt4, W. Klein-Hessling4, Z. Xu5, M. Povilaitis6, L. Kubisova7, Z. Parduba8,
S. Paci9, N.B. Siccama10, M.H. Stempniewicz10
1 IRSN, PSN-RES/SCA, Saclay, France2 Electricité de France, EDF R&D, Chatou, France3 RSE, Milano, Italy4 GRS, Berlin/Köln, Germany5 IKET, KIT, Karlsruhe, Germany6 LEI, Kaunas, Lithuania7 UJD SR, Bratislava, Slovakia8 UJV Rez, Czech Republic, 9 DIMNP, Pisa University, Pisa, Italy10 NRG, Safety & Power, the Netherlands
ERMSAR 2012, Cologne, Germany, March 21 – 23, 2012
Content
IntroductionPresentation of the experimentsPresentation of the benchmark participantsCode-experiment comparison exerciseResults analysisConclusions
Content
IntroductionPresentation of the experimentsPresentation of the benchmark participantsCode-experiment comparison exerciseResults analysisConclusions
- 4
Introduction
PTR
Pump
Reactor enclosure
Spray nozzles
PTR
Pump
Reactor enclosure
Spray nozzles
Context •Severe accident •Mitigation •Spray systems in the containment vessel
Spray nozzles•~ 500 nozzles•4 different rings/ramps•Flow rate: 280 kg/s per ramp•Temperature : 20° - 60°C
Spray systems – main effects
- 5
Fissionproductswash-outHydrogen
mixing
SPRAYSYSTEMS
Pressurereduction
Spray systems – follow-up of SARNET activities separate effect tests in SARNET-2
- 6
Fissionproductswash-outHydrogen
mixing
SPRAYSYSTEMS
Pressurereduction
Condensation on droplet
Benchmark #1
Gas mixture entrainment by
sprays
Benchmark #2
SARNET-2 WP7 :
ContainmentWP7-2, Task 1:
Spray activities
- 7
Synthesis of the activities
•Specification•Nov. 2009: Delivery of the specifications•Dec. 2009: Specification meeting
•Calculations•Feb. To June 2010: Delivery of the blind and later open calculations (10 institutions, 10 codes, 15 contributions)
•Benchmark analysis•July 2010: Code-experiment comparison meeting•July 2010: Delivery of the code-experiment comparison report•Final diffusion: March 2011•Presentation at the NURETH 2011 conference
Content
IntroductionPresentation of the experimentsPresentation of the benchmark participantsCode-experiment comparison exerciseResults analysisConclusions
- 9
1st Elementary benchmark - HMT on droplets
•Single droplet fall (monodisperse size distribution)
–Injected droplets:- 300 - 700 µm- 2 - 5 m/s- 20 - 40°C
•Air-steam homogeneous and steady mixture
–1 - 5 bar
–20 - 140°C
–3 - 90%
Vd
DdTd
Vd_Z2
Dd_z2Td_z2
Vd_Z1
Dd_z1Td_z1
Z2
Z1
Initial
TgP
RHat rest
Content
IntroductionPresentation of the experimentsPresentation of the benchmark participantsCode-experiment comparison exerciseResults analysisConclusions
- 11
Benchmark participantsInstitution Code name Institution Code name
KIT KIT specific spray model GRS COCOSYS v.2.4 IVO
EDF NEPTUNE_CFD v. 1.0.7 GRS COCOSYS v.2.4 MARCH
ERSE (RSE) ECART - standard model 4W UJV MELCOR v. 1.8.6 YV
ECART -"ad hoc" model 4W* UJD COCOSYS v. 2.3v24
NRG ANSYS FLUENT v. 6.4.11 UJD ASTEC v. 2.0
NRG SPECTRA LEI COCOSYS v. 2.3IRSN ANSYS CFX v. 12 UNIPI FUMO
IRSN ASTEC CPA v. 1.3 rev3
10 institutions, 10 codes, 15 contributions
Content
IntroductionPresentation of the experimentsPresentation of the benchmark participantsCode-experiment comparison exerciseResults analysisConclusions
Overall code-experiment comparison
- 13
SARNET-2 - Elementary spray benchmark on single droplet HMTIRSN experiments
Z = 2.51 m - OPEN exercise
-20%
-15%
-10%
-5%
0%
5%
10%
15%
20%
EVAP
3
EVAP
13
EVAP
18
EVAP
21
EVAP
24
COND
1
COND
2
COND
7
COND
10
TEST
Rel
ativ
e er
ror
on d
ropl
et
dia
met
er (%)
EDF - NEPTUNE
NRG - FLUENT
IRSN - CFX
KIT - Dev. Model
ERSE - ECART Ad hoc model
UNIPI - FUMO
GRS - COCOSYS - IVO model
UJD - COCOSYS
LEI - COCOSYS
UJV - MELCOR
UJD - ASTEC/CPA
IRSN - ASTEC/CPA
- 14
Code-experiment comparison – CFD codesHMT on IRSN single droplet testsEDF - NEPTUNE V.1.0.7 - BLIND
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
drop
let
diam
eter
(µm
)
Z = 4.39 mY = X+/-10%
HMT on single droplet testsIRSN - CFX
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
drop
let
diam
eter
(µm
)
Z = 4.39 mY = X+/-10%
HMT on IRSN single droplet testsNRG - FLUENT
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
drop
let
diam
eter
(µm
)
Z = 4.39 m BLINDZ = 4.39 m OPENY = X+/-10%
HMT on IRSN single droplet testsKIT - Model under development
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
drop
let
diam
eter
(µm
)
Z = 4.39 m BLINDZ = 4.39 m OPENY = X+/-10%
- 15
Code-experiment comparison – ECART, FUMO, MELCOR codes
HMT on IRSN single droplet testsERSE - ECART - "ad hoc"
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
drop
let
diam
eter
(µm
)
Z = 4.39 m BLINDZ = 4.39 m OPENY = X+/-10%
HMT on IRSN single droplet testsUNIPI - FUMO - BLIND
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
drop
let di
amet
er (µm
)
Z = 4.39 mY = X+/-10%
HMT on IRSN single droplet testsUJV - MELCOR
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
dro
ple
t dia
met
er (µm
)
Z = 4.39 m - BLINDZ = 4.39 m - OPENY = X+/-10%
- 16
Code-experiment comparison COCOSYS and ASTEC codes
HMT on IRSN single droplet testsGRS - COCOSYS - EVO Model
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
drop
let
diam
eter
(µm
)
Z = 4.39 m BLINDZ = 4.40 m OPENY = X+/-10%
HMT on IRSN single droplet testsUJD - ASTEC V. 2.0
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Measured droplet diameter (µm) (I. C. 95%)
Cal
cula
ted
dro
ple
t dia
met
er (µm
)
Z = 4.39 m BLINDZ = 4.39 m OPENY = X+/-10%
0
100
200
300
400
500
600
700
800
0 100 200 300 400 500 600 700 800
Cal
cula
ted
drop
let
diam
eter
(µ
m)
Measured droplet diameter (µm) (I. C. 95%)
HMT on IRSN single droplet testsIRSN - ASTEC/CPA
Z = 4.39 mY = X+/-10%
- 17
Main conclusions of code-experiment comparion
1.Low user-effect
2.A general good agreement between codes and experiments, but...
3.… large differences obtained for some specific tests
4. To undersand these differences detailed look on the mass transfer expressions next section
Content
IntroductionPresentation of the experimentsPresentation of the benchmark participantsCode-experiment comparison exerciseResults analysisConclusions
- 19
Mass flux expressions – detailed look
bd
d
drefmd
masss D
ShTDDQ
2
mref
n
refdd TScTBASh Re
Diffusion coefficient
Reference temperature
« density term »
In all codes, the droplet mass flux expression can be expressed with the same general expression below
… but different « detailed » choices are made
- 20
« Density term » : different expressions in codes
For the ASTEC code, the expression is given by:
ds
dsbulksfilmmsbd TX
TXXTcM
1,
2
where 2
2filmpg
filmm TR
PTc (so-called average molar concentration in ASTEC).
And P
TPTX dsatds
F o r t h e M E L C O R c o d e , t h e e x p r e s s i o n i s g i v e n b y :
1
1ln ,
ds
dsbulksbulkmbd TY
TYYT
W h e r e bulkabulksbulkm TTT ( s o - c a l l e d d e n s i t y o f t h e a t m o s p h e r e i n M E L C O R ) .
For the UNIPI code, this expression is given by:
ds
bulksfilmmsbd TX
XTcM
1
1ln ,
1
where 1
1filmpg
filmm TR
PTc (so-called the “film” mixture molar concentration in the code).
For the COCOSYS code (IVO model), this expression is given by:
dsbulksfilmmbd TYYT ,
where 2
dsatbulksfilmm
TTT
(so-called the average steam density in COCOSYS).
F o r t h e C F X c o d e , t h i s e x p r e s s i o n i s g i v e n b y :
bulks
dsbulkm
bulkm
sbd X
TXT
M
M
,, 1
1ln
W h e r e bulkpg
bulkmbulkm TR
PMT ,
A n d sbulksabulkabulkm MXMXM ,,,
- 21
Differences in « density terms »
SARNET-2 - Elementary benchmark on HMT on single droplets Relative difference between the different codes results and the ASTEC results on the Gamma term (so-called "density term" in the mass flow-rate expression)
- Z = 0 m
-120
-100
-80
-60
-40
-20
0
20
40
60
80
E3 E13 E18 E21 E24 C1 C2 C7 C10
Test
Rela
tive
diff
eren
ce
[(co
de-A
STEC
)/AST
EC]
[%]
MELCORUNIPICOCOSYS (with correction)CFX
From to -100% to + 60% relative differencesbetween the participants
« density terms »
- 22
Diffusion coefficient
SARNET-2 - Elementary benchmark on HMT on single dropletsRelative difference between diffusion coefficients given by two participants
and different expressions calculated independently on the basis of the experimental results
-40%
-20%
0%
20%
40%
60%
80%
100%
Test
Rela
tive
diff
eren
ces
UNIPI/ FULLER_TBULKCOCOSYS/ UNIPIUNIPI/ WILKE_LEE_TBULKUNIPI/ FULLER_TFILM1
From -20% to over 100%differences between
participantsfor the steam diffusion
coefficient in the mixture
- 23
Reference temperature
Reference temperature in the participants codes
-droplet temperature Td, -bulk temperature Tbulk, -the mean value Tfilm1 between droplet and bulk temperature, -so-called 1/3 law temperature Tfilm2, i.e. a value pondered by 1/3 of the bulk temperature and 2/3 of the droplet temperature.
- 24
Reference temperature
Overall differences on the mass flux over the droplet due to the choice of the reference temperature used in diffusion coefficient - at Z = 0 m
-100%
-50%
0%
50%
100%
150%
200%
E3 E13 E18 E21 E24 C1 C2 C7 C10
Test
Rela
tive
diff
eren
ce (
%)
Tbulk/ Tfilm2
Tfilm1/ Tfilm2
Td/ Tfilm2
Overall differences on the mass flux over the droplet due to the choice of the reference temperature used in kinematic viscosity in the Schmidt number - at
Z = 0 m
-10%
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
E3 E13 E18 E21 E24 C1 C2 C7 C10
Test
Rela
tive
diff
eren
ce (
%)
Tbulk/ Td
Tfilm1/ Td
Tfilm2/ Td
From -20% to over 100%differences between
participantsDepending on the way the reference temperature is
calculated
- 25
Analysis of benchmark differences between codes/tests
The different parameters in the mass flux expressions lead to several « errors » that can
compensate together or be enhanced
Can we find the reason why these « errors » are small in some tests, and largers in other
tests ?
The post-processing of partners data has shown 2 relevant parameters (next slide)
- 26
Relevant parameters
VdDdTdInitial conditions
Droplet residence time
Relative mass variation
compared to droplet mass
Table 1: Average residence time of the droplet and associated standard deviation at Z = 2.51 m(average value calculated from MELCOR, UNIPI, COCOSYS and ASTEC/ CPA calculations) ; ASTEC mass
flux at Z = 0 divided by the initial droplet mass md
Test Mean residence time (s) at Z =2.51 m
Associated standarddeviation (s)
Qsmass
/ md (Z = 0)
EVAP3 0.914 0.05 0.058EVAP13 1.716 0.069 0.605EVAP18 2.116 0.035 2.722EVAP21 3.036 0.361 1.991EVAP24 4.813 0.712 4.07COND1 2.09 0.259 0.942COND2 2.166 0.24 0.717COND7 1.485 0.044 0.112COND10 0.99 0.031 0.115
- 27
SARNET-2 - Elementary spray benchmark on single droplet HMTIRSN experiments
Z = 2.51 m - OPEN exercise
-20%
-15%
-10%
-5%
0%
5%
10%
15%
20%
TEST
Rela
tive
err
or o
n d
ropl
et
dia
met
er (
%)
EDF - NEPTUNE
NRG - FLUENT
IRSN - CFX
KIT - Dev. Model
ERSE - ECART Ad hoc model
UNIPI - FUMO
GRS - COCOSYS - IVO model
UJ D - COCOSYS
LEI - COCOSYS
UJ V - MELCOR
UJ D - ASTEC/CPA
IRSN - ASTEC/CPAFor tests with drops having larger residence timein case of larger mass flux compared to the droplet mass, « errors » in the code expressions are seen more clearly
Explanation of the large differences between codes for some tests
Content
IntroductionPresentation of the experimentsPresentation of the benchmark participantsCode-experiment comparison exerciseResults analysisConclusions
- 29
Main conclusion
Differences obtained in some specific tests are due to many different choices done by the code developer for the modelling
And are clearly observed for tests with: Higher droplet residence time Higher mass transfer rate/compared to droplet mass
ratio
Be aware of having validating your model under different conditions if you want to increase your code predictability
1 test is not enough to validate one phenomenon, a range of tests improves the code validation on this phenomena
Consequences for spray calculations in containment analysis
• It is difficult to say in advance what will be the main effects if wrong choices are made in the droplet HMT modelling, since phenomena are coupled, but…
• Possible larger errors, if wrong parameters are used in the mass flux expressions, can be assumed :- In case severe accident Thy conditions AND for small droplets
- In case of droplet evaporation (H2 when spraying is activated)
- In case of larger residence times if saturation is not reached (allowing changes in the droplet size due to mass transfer)
- 30
How far is this benchmark from reactor applications ?
- same Thy conditions- same range of droplet sizes- no pressure variation, so different droplet
thermodynamical equilibrium
- different droplet velocities- no gas entrainment, so different droplet
dynamical equilibrium- no turbulence
Spray systems – SARNET-2 Benchmarks
- 32
Hydrogen mixing
SPRAYSYSTEMS
Pressurereduction
Condensation on droplet
Gas mixture entrainment by
sprays
Benchmark #1 Benchmark #2
SARNET-2 WP7 :
ContainmentWP7-2, Task 1 : Spray activities
- 33
Status of the next elementary benchmark
Tests in the IRSN CALIST facility Real PWR spray nozzle (2 m
« diameter » spray) Real-scale experiment for spray
entrainment
Benchmark specificaions: nov. 2011
Partners contributions received Received in February 2012 (FLUENT,
CFX, NEPTUNE, GASFLOW, ECART, FDS)
Last contributions until March 31st 2012
Synthesis report in 2012
After SARNET-2, we will be close to be able to calculate real size spray systems in a reactor using accurate CFD
tools or advanced spray LP modelling
Coupled phenomenaThe zone of droplet characterisitcs variation is « small »
compared to the size of the containment building BUT is the place of strong exchanges:
CFD calculations could bring some insights if the reactor meshed zone is reduced to few meters below the nozzles!
Hydrogen mixing
SPRAYSYSTEMS
Pressurereduction
Coupled phenomena
Thanks!
- 36
1st Elementary benchmark - HMT on droplets
Test P [bar] Tgas [°C] HR [%] Td [°C] Dd [µm] Ud [m/s] EVAP3 1.00 20.1 20.5 20.6 611+/-4 3.58
EVAP13 5.42 100.1 15.0 31.0 605+/-4 3.75 EVAP18 1.00 135.2 3.0 30.9 309+/-5 3.66 EVAP21 4.29 97.4 12.0 29.2 311+/-7 3.63 EVAP24 4.97 135.0 4.0 30.3 296+/-4 3.10 COND1 4.00 141.3 55.0 36.0 341+/-2 4.90 COND2 4.80 141.6 71.0 37.0 344+/-2 4.70 COND7 5.30 139.3 87.0 35.0 593+/-11 2.10
COND10 2.40 121.5 79.0 16.0 673+/-5 2.10
Main thermodynamical exchanges for spray occur in a small region:Vertical evolution of the droplet size and temperature
HMT ON SINGLE DROPLET - IRSN TEST - COND7
500
520
540
560
580
600
620
640
660
0.0 1.0 2.0 3.0 4.0 5.0 6.0
Z (m)
Dd (µm
)
UNIPI LEI - COCOSYS UJV - MELCORERSE- ECART TRADI ERSE - ECART 1DROP NRG - FLUENTUJD - ASTEC IRSN - ASTEC UJD - COCOSYSGRS - COCOSYS MARCH GRS - COCOSYS IVO EDF - NEPTUNEKIT - Dev. model IRSN - CFX NRG - SPECTRA
HMT ON SINGLE DROPLET - IRSN TEST - COND7
0
20
40
60
80
100
120
140
160
0.0 1.0 2.0 3.0 4.0 5.0 6.0
Z (m)
Td
(°C)
UNIPI LEI - COCOSYS UJV - MELCORERSE- ECART TRADI ERSE - ECART 1DROP NRG - FLUENTUJD - ASTEC IRSN - ASTEC UJD - COCOSYSGRS - COCOSYS MARCH GRS - COCOSYS IVO EDF - NEPTUNEKIT - Dev. model IRSN - CFX NRG - SPECTRA
Condensation
Evaporation
Equilibrium temperature
Increase of droplet
temperature
Main variations of droplet sizes due to HMT in the first meter of droplet fall