Kurchatov Institute
Hydrogen Subsonic Upward Release and Dispersion Experiments in Closed Cylindrical Vessel
Hydrogen Subsonic Upward Release and Dispersion Experiments in Closed Cylindrical Vessel
Denisenko V.P.1, Kirillov I.A.1, Korobtsev S.V.1, Nikolaev I.I.1, Kuznetsov A.V.2, Feldstein V.A.3, Ustinov V.V.3
1 RRC ”Kurchatov Institute” 1, Kurchatov Sq., Moscow, 123182, Russia 2 NASTHOL 6, Shenogin str., Moscow, 123007, Russia 3 TsNIIMash 4, Pionerskaya, Korolev, 141070, Russia
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Context: Russian R&D Programme “Codes an Systems for Hydrogen Safety”
grant of Russian Ministry of Science and Education (2004-2006, cont. July 2007-2009):
for safety provision of national hydrogen infrastructure
• scientific basis for development of regulatory documents (codes/standards) …minimal number and allocation of sensors in confined areas …
• prototypes for subsequent commercialization of tools/components forintegrated safety systems
… sensors
recombinersinhibitors…
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Context: Problem: Allocation of sensors in confined areas
Technical questions:
1. How many ? What is a minimal number of gas detectors, which should be used in confined area, for safety provision ?
2. Where ?How should they be spatially allocated?
Land use problem: absence of free space -> multiple-use of space -> confined sites
undeground parking, 100+, ~5 kg H2 per auto
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Context: Problem: Allocation of sensors in confined areas
Practical reference case:
according to current technical regulation of Ministry of Transport (VCN 01-89 Minavtotrans)Ministry of Emergency (NPB 105-03)
gas*-fueled autotransport facilities and premises (parking, workshop, etc.) of category A should be equipped with gas-analyzers and alarm systems
* - propane-buthane
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Context: Problem - Allocation of sensors in confined areas
Empirical approach: Qualitative guidelines
“…Sensors should be positioned to detect any gas accumulation before it creates a serious hazard….”
The selection and use of flammable gas detectors, HSE, TD05/035, 2004 (p.8)
“…Hydrogen detectors are typically placed above a likely leak point, where hydrogen may accumulate, and at the intake of ventilation ducts….” ISO-TR-15916 (p.5)
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Empirical approach: Quantitative guidelines
TU-gas-86. Requirements on arrangement of the indicators and gas-analysers
RD BT 39-0147171-003. Requirements on arrangement of stationary gas-analysers in industrial facilities and on outdoor sites of oil and gas industry
1 sensor per 100 m2
Restricted application: for propane-buthane only
Context: Problem - Allocation of sensors in confined areas
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Practical need:
Quantitative engineering guidelines (rational procedure) for selection of
• a minimal number of sensors and
• their spatial allocation within given confined space, which should be protected
Research prior art:
indirect relevance only
• Extensive database for jets/plumes under open space conditions
• For releases into confined space – fire detectors allocation studies
Context: Problem - Allocation of sensors in confined areas
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Scope of reported research work:
Overall goal• experimental characterization of the
hydrogen sub-sonic* release and distribution inside of confined, unventilated space
baseline (reference) data for subsequent studies:certain, accurate, repeatable, verifiable
Technical objectives • qualitative characterization of basic gas-dynamic patterns • quantitative measurements of ignitable envelope evolution
* - “small foreseeable leakage” scenario
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Approach: “Schiphol principle”: Mind your uncertainties !
• minimize experimental uncertainties ALAPR
identify and document uncertaintiesbalance ‘performance - uncertainty“ propose affordable design of experiment
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Source of uncertainty Variable Is controlled by Effect
boundary conditions chamber geometry rigid walls "membrane effects" are absent
external thermal fluxes temperature differenceexternally-driven convective effects are absent
external mass fluxes gas-tight head leakage effects are absent
initial conditions gas pressure pressure gauge in gas FL +
gas temperature temperature sensor in gas FL +
relative humidity of gas RH sensor +
performance conditions chemical composition field net of chemical sensors +
temperature field net of tenperature sensors +
instrumentation sensor size ?
sensor geometry cylindrical ?
sensor positioning horizontal ?
data acquisition fault-tolerant design design +
test procedure inert gas purging procedure +
Approach: Analysis of experimental uncertainties
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Schematic drawing of protective concrete dome (R = 6 m, h = 6 m, H = 12 m)
Ambient conditions (inside of dome):Air temperature 23ºCAir pressure 758 mm HgRelative humidity 64 %
Experiment: Site layout
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External (left) and internal (right) views of the experimental chamber
Experiment: Experimental chamber
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Experiment: Gauge net layout
2,22 м
hydrogen source: circular tube (internal diameter - 0,012 m)
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Thermal Conductivity Gauge TCG-3880(is shown with open cap)by Xensor Integration (Netherlands)
Acoustic sensor mounted at electronic card (for data processing and transmission) by RRC ”Kurchatov Institute”
Experiment: Hydrogen sensors
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gas mixture preparation device (GMPD):
gas mixture composition up to 8 components
steady gas flow rate [5*10-6 , 7*10-4 ] m3/s (from 20 to 2560 l/h).
Experiment: Gas supply and control
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Experiment: Procedure and Parameters
Series3 consecutive runs (inert gas purging between) with the same parameters
Ambient conditions standard
Hydrogen injectiondirection upwardduration 10 minflowrate 0,46 l/sec
Data acquisitionDuration during injection and 15 min after its endTemperature sensors 24 (inside), 4 (outside)Hydrogen sensors 24 (inside)Pressure gauge 1 (inside), 1 (outside)
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Time histories for the hydrogen concentrations (% vol.) for the 24 gauges (time duration 0 - 25 min)
Experiment: First results: Hydrogen concentration time histories
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Three-phase evolution of ignitable gas mixture cloud
Step 1 – upward propagation of emerging jet/plume,
Step 2 – impinging of jet/plume with ceiling and outward expansion of cloud,
Step 3 – downward expansion of cloud from ceiling to floor.
Experiment: First results: Basic flow patterns: Pre-test simulations
Evolution of Ignitable Hydrogen-Air Gas Mixture Cloud
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Evolution of Ignitable Hydrogen-Air Gas Mixture Cloud
1 min
5 min
10 min
10,05 min
15 min
25 min
hydrogen concentration in % vol.
Experiment: First results: Basic flow patterns: Experimental results
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Definition of averaged speed using sensor 4 and sensor 21
Averaged speed of envelope (2 % vol.) front propagation
UNVENT#1 series (3 runs)
envelope propagation speed
Vert. (upward) - 0,33 m/sec, Horiz.(outward) - 0,055 m/sec.
Experiment: First results: Experimental data for ignitable mixture front speed
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Time histories for three different test runs (sensor 10)
Experiment: First results: Reproducibility of results
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Experiment: Synchronous behavior of sensors at symmetric points
Symmetrical character of hydrogen flow in experimental vessel
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The experimental set-up for pre-normative studies of hydrogen release and dispersion inside of a medium-scale (4 m3), closed horizontal cylindrical vessel was prepared and adjusted.
The first precise measurements (3 test runs) of the time evolution of explosive hydrogen cloud after hydrogen injection under the well-controlled boundary/initial conditions have been carried out using spatially distributed 24 hydrogen sensors and 24 thermocouples.
Analysis of the simultaneous experimental records for the different spatial points permits to delineate the basic flow patterns of hydrogen subsonic release in closed vessel in contrast to hydrogen jet release in open environment.
The quantitative data were obtained for the averaged speeds of ignitable cloud envelop (50% fraction of the Lower Flammability Limit (LFL) – 2 vol.%) propagation in the vertical and horizontal directions.
It was proposed to use the uncertainty analysis of the experiments and simulations for benefit of the hydrogen safety studies
Conclusions:
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ACKNOWLEDGMENTS
This work was supported by
• Russian Ministry of Science and Education and
• EU HYPER project (partially).
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Thanks for your attention !
Questions/comments:
Thanks for your attention !
Questions/comments:
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SBEP-V1
From: www.hysafe.org/download/362/D23-01.doc
D=5.5 m
D=2.2 m
Figure 1. (a) Shape of the experimental vessel
0.001
0.010
0.100
1.000
10.000
0.0 1.0 2.0 3.0 4.0 5.0 6.0
Distance from top (m)
Cp
/ Co
BRE BRE-A NCSaNCSb FZJ FZKGXC UUa UUbCEA WUT DNVUPM INR Cp / Co = 1Cp / Co = 2 Cp / Co = 1/2
Figure 8. Comparison between models (250 min after the end of release).
Experiment vs Simulation(VNIIPO, 1988) (HySafe, 2005)
Context: Problem – Uncertainties in hydrogen safety studies
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D=5.5 m
D=2.2 m
Experimental uncertainty: during measurement phase (250 min), it was impossible to control the thermal boundary conditions
Context: Problem – Uncertainties in hydrogen safety studies
SBEP-V1