ICHS-4, 12-15 Sept. 2011, San Francisco, USA

A.G.Venetsanos1, I. Tolias1, D. Baraldi7, S. Benz5, B. Cariteau2, J. Garcia3, O.R. Hansen4, C. Jäkel6, S. Ledin8, P. Middha4, E.A. Papanikolaou7

1 Environmental Research Laboratory, National Centre for Scientific Research Demokritos (NCSRD), 15310 Aghia Paraskevi, Attikis, Greece, venets@ipta.demokritos.gr2 C.E.A. Saclay, D.E.N., D.M.2S., S.F.M.E., Laboratoire d’Etude Expérimentale des Fluides, 91191 Gif/Yvette cedex FRANCE3 Escuela Técnica Superior de Ingenieros Industriales, Universidad Politécnica de Madrid (UPM), José Gutiérrez Abascal, 2, E-28006 Madrid, Spain4 GEXCON AS, Fantoftvegen 38 Box 6015 Postterminalen N-5892 BERGEN Norway5 IKET, KIT, Postfach 3640, 76021 Karlsruhe, Germany6 Forschungszentrum Juelich (FZJ), 52425 Juelich, Germany7 Joint Research Centre of the European Commission (JRC), Institute for Energy, 1755 ZG Petten, The Netherlands8 Health and Safety Laboratory (HSL), Harpur Hill, Buxton, Derbyshire, SK17 9JN, UK

IA-HySafe Standard benchmark exercise SBEP-V21: Hydrogen release and accumulation within a non-ventilated ambient pressure garage at low release rates

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

CONTENTS

Introduction & Scope Description of CEA Garage Test 5 Modelling strategy Results & discussion Conclusions

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ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Intro & Scope

The Research Committee activities of IA-HySafe include: the continuation of SBEPs first introduced within HySafe EC-NoE

SBEPs to validate, inter-compare and further develop existing

Computational Fluid Dynamics (CFD) codes and models in predicting hydrogen related release, dispersion and combustion phenomena

Focus in the present work: Understanding and prediction of the dispersion / accumulation

of hydrogen releases in confined spaces under low release conditions

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ICHS-4, 12-15 Sept. 2011, San Francisco, USA

CEA Garage Test-5

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Garage x-dimension (mm) 5760

Garage y-dimension (mm) 2960

Garage z-dimension (mm) 2420

x release (mm) -2880y release (mm) 1480z release (mm) 220

Exit diameter (mm) 29,7Volumetric flow rate - STP

(NL/min)18

He mass flow rate (g/s) 0,054

Garage Temperature T (°C) 24,1

Exit velocity (m/s) 0,47Release Direction Upwards

Release Type ContinuousRelease duration (s) 3740

Released volume - STP (NL) 1122

He released mass (gr) 200,28

Target concentration (%) 2,94%

Total measurement time (s) 90440

Re = 115

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Modelling strategy

5

Participant/

Code

Turbulence

model

Number of computational

cells

Convective terms

Transient terms

Vent model

Molecular diffusivity

(m2/s×10-5)

FZJ/CFX SAS-SST212272 (half

garage)2nd order

2nd order backwards

EulerOpening 8.0

GEXCON/FLACS

k-εRelease: 30888Diffusion: 4560

2nd order Opening 2.0

GEXCON_revised/FLACS

k-εRelease: 44352Diffusion: 7200

2nd order Extension 2.0

HSL/CFX SST 88840

High resolution

scheme (2nd order)

2nd order backwards

EulerOpening 1.86

JRC/CFX LaminarRelease: 101401Diffusion: 70429Outside: 5173

2nd order2nd order

backwards Euler

2 m × 3 m × 3 m

extension11.7

KIT/GASFLOW

k-ε 58905Upwind 1rst

orderALE scheme Opening 7.5

NCSRD/ADREA-

HFk-ε

53760Outside: 3360

SMART 3rd order

1rst order fully implicit

1 m × 2.96 m × 2.42 m extension

5.65

UPM/FLUENT

Laminar 125516 2nd order1rst order

fully implicitOpening 5.65

UPM_revised/

FLUENTLaminar -

1 m × 2.96 m × 2.42 m extension

5.65

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results – Mass balance

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ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results – CPU times

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Participant/Code Compressibility Simulated period (s) CPU time Threads Computer type

FZJ/CFXFully

compressible20000 s 15d, 21h 3 Intel i7 860 CPU

GEXCON/FLACS

Low Mach 100000 s 1d 1Linux-PC, Intel Xeon

W3550, 3.07 GHzGEXCON_revi

sed/FLACS

Low Mach 20000 s 5.5h 4 Quad core

HSL/CFXFully

compressible

15000 s (coarse mesh) 12000 s

(fine)

18d, 5h (coarse) 19d,

15h (fine)2

Windows XP SP3 64-bit, 2 Intel Xeon

JRC/CFXFully

compressible15000 s 9d, 20h 8 3.25 GHz

KIT/GASFLOW

Low Mach 20000 2d, 15h 1Suse Linux 11.2, i7-

950, 3.06GHz

NCSRD/ADREA-HF

Fully compressible

7080 10d 2Windows 7, i7 M620

CPU at 2.67 GHz

UPM/FLUENT

Fully compressible

20000 13d 4Windows 7, 2 Intel

Xeon Quad Core CPUs at 2.4 GHz

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

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Sensor name z (mm)P1N3 2370P1N2 2135P1N1 1900M1N5 1575M1N4 1260M1N3 945M1N2 630M1N1 315

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

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P1N3, z = 2.37 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

10

P1N2, z = 2.135 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

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P1N1, z = 1.9 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

12

M1N5, z = 1.575 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

13

M1N4, z = 1.26 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

14

M1N3, z = 0.945 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

15

M1N2, z = 0.63 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

Results - Concentrations

16

M1N1, z = 0.315 m

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

CONCLUSIONS

Relatively good predictions of He concentrations

Significant reduction in CPU time with low Mach number solvers

Significant effect of extending the computational domain far enough beyond the confined space opening.

ICHS-4, 12-15 Sept. 2011, San Francisco, USA

THANK YOU FOR YOUR ATTENTION

ANY QUESTIONS