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Mit
glie
d d
er
Helm
holt
z-G
em
ein
sch
aft
Simulation of the efficiency of hydrogen recombiners as safety devices
Ernst-Arndt Reinecke, Stephan Kelm, Wilfried Jahn, Christian Jäkel, Hans-Josef Allelein
International Conference on Hydrogen Safety
September 12-14, 2011, San Francisco, CA
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 2E.-A. Reinecke et al.
Overview
Simulation of the efficiency of hydrogen recombiners as safety devices
Passive auto-catalytic recombiner (PAR) Goal of the numerical study Scenario investigated Model approach Results
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 3E.-A. Reinecke et al.
Unintended H2 release inside confined space
safety measure device
detection sensor
release interruption automatic valve
avoid hydrogen accumulation and ignition/explosion
ventilation
recombiner
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 4E.-A. Reinecke et al.
Passive auto-catalytic recombiner (PAR)
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 5E.-A. Reinecke et al.
Commercial PARs in Nuclear Power Plants
Vendors AECL, Canada AREVA, France/Germany NIS, Germany
Source: Siempelkamp
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 6E.-A. Reinecke et al.
Operational boundary conditions
NPP containment large temperature and density gradients large natural convection loops large geometry (20,000-70,000 m³, typical length scales 5-50 m) steam-inertized in early accident phase
Typical H2 and FC applications significant smaller scales different thermal hydraulic conditions
NPP PAR applicability ? H2 & FCGOAL:
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 7E.-A. Reinecke et al.
Scenario
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 8E.-A. Reinecke et al.
Source: CEAExperiment
GARAGE facility at CEA/France single vehicle private garage (~40 m³) concentration measurement at ~60 pos.
Test 1: He release (~2 g/s) for ~2 min
data recently published:Gupta et al., Int J Hydrogen Energy 34 (2009) 5902–5911
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 9E.-A. Reinecke et al.
Release scenario and measurement locations
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 10E.-A. Reinecke et al.
Approach
Scenario based on GARAGE experiment (CEA)
1. Simulation of the helium release and distribution scenario and validation against experimental data
2. Replace helium by hydrogen and verify the calculated distribution
3. Add a PAR to the scenario and compare mitigated/unmitigated scenario
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 11E.-A. Reinecke et al.
Model approach
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 12E.-A. Reinecke et al.
Coupled Modeling Approach
Macro ScaleMeso ScaleMicro Scale
REKO-DIREKT(in-house)
ANSYS CFX
H2-Injection
Vent
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 13E.-A. Reinecke et al.
PAR model: REKO-DIREKT
Input: T, yi, p
Output: T, yi, m
chemical (catalytical)
reaction
natural convection
Ch
imn
eyC
atal
yst
sec
tio
n
mass/heat transfer
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 14E.-A. Reinecke et al.
T / °CyH2 / Vol.-%
CFX REKO-DIREKT - Inlet gas temperature- Inlet gas composition- Pressure
REKO-DIREKT CFX - Outlet gas temperature- Outlet gas composition- Mass flow through PAR
REKO-DIREKT CFX
REKO-DIREKT
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 15E.-A. Reinecke et al.
Results
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 16E.-A. Reinecke et al.
Unmitigated release - setup
Physical Model: Half Symmetry RANS equations Ideal gas equation of state Isothermal SST-model incl. buoyancy prod. & dissipation Injection
• He: 240 g (1,99 g/s)• H2: 120 g (0,99 g/s)
Wall functions at inner walls Vent: Outlet Boundary
H2-Injection
Vent
Grid statistics:Nodes 214.272y+ < 250face angle > 45°aspect ratio < 49volume ratio < 14
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 17E.-A. Reinecke et al.
Helium/Hydrogen concentration profiles
0
500
1000
1500
2000
2500
0% 1% 2% 3% 4% 5% 6% 7% 8% 9%He / H2 fraction [vol.%]
z -
axis
[m
m]
Experiment
CFX - Helium
CFX - Hydrogen
30 s 60 s 90 s 120 s
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 18E.-A. Reinecke et al.
H2-Injection
Vent
Mitigated release - setup
Physical Model: Half Symmetry RANS equations Ideal gas equation of state SST-model incl. buoyancy prod. & dissipation Injection
• H2: 120 g (0,99 g/s) Wall functions at inner walls
+Fixed Wall Temperature +Temperature dependent properties+No heat radiation Vent: Outlet Boundary
AREVA PAR type FR90-150
Inlet Boundary
Outlet Boundary
Adiabatic WallsGrid statistics:
Nodes 203.385y+ < 70face angle > 45°aspect ratio < 49volume ratio < 16
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 19E.-A. Reinecke et al.
Comparison mitigated/unmitigated scenario
800 s
240 s
120 s
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 20E.-A. Reinecke et al.
Comparison mitigated/unmitigated scenario
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 21E.-A. Reinecke et al.
Details mitigated scenario
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 22E.-A. Reinecke et al.
PAR model details
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 23E.-A. Reinecke et al.
Flammable cloud volume histories
0
5
10
15
20
25
0 200 400 600 800 1000
time [s]
flam
mab
le v
olum
e (>
4 vo
l.% H
2) [m
³]
with PAR
unmitigated
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 24E.-A. Reinecke et al.
Performance (estimates)
Processor 1 CPU Quadcore I7-860, 2.8 GHz Open Suse Linux 11.3 CFX 12.1
Calculation time (1200 s) unmitigated scenario: ~10 d mitigated scenario: ~40 d
REKO-DIREKT: ~6 min more time steps more gas components (H2+O2+N2+H2O)
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 25E.-A. Reinecke et al.
Conclusions
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 26E.-A. Reinecke et al.
Conclusions (1/2)
Goal investigate the applicability of PAR from NPP containment to typical
H2&FC application significant differences in operational boundary conditions
first study based on GARAGE experiment, performed with ANSYS-CFX and REKO-DIREKT
Results H2 injection of 1.5 m³, flammable cloud was removed within 10
minutes hot exhaust plume promotes the transport of hydrogen rich gas
mixture towards the PAR inlet
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 27E.-A. Reinecke et al.
Conclusions (2/2)
Next steps parameter variation
injection rate, location, and direction PAR design and number geometry of the enclosure
consideration of possible PAR ignition scenarios validation against mitigation experiments in new multi-compartment
facility, currently under construction at JÜLICH
ICHS-4September 12-14, 2011, San Francisco, CA
Folie 28E.-A. Reinecke et al.
Thank you for your attention !