The International Energy Agency Hydrogen Implementing Agreement Task on Hydrogen Safety

International Energy Agency Hydrogen Implementing AgreementVision: The IEA HIA envisions a hydrogenfuture based on a clean,sustainable energy supply thatplays a key role in all sectors of theglobal economy.Mission: Accelerate hydrogen implementation and widespread utilization.Strategy: Task shared programs ofCoordinated, innovative researchDevelopment and demonstrationInformation exchangeTo eliminate or reduce safety related knowledge gaps, or insufficient data that inhibit the accelerated and widespread use of hydrogen energy:facilitate risk informed codes and standards;permitting and siti

Synthesis of the Conference

Releases:Impinging and wall attached jets and jet fires withthe associated heat transfer to set conditions for safe blowdownProperties and behaviour of cold hydrogen fromliquid releases Evaluate the effects of various LH2 spill quantities, spill-and-surrounding configurations, atmospheric conditions, ignition energy, and ignition time delays on resultant blast hazards.Further the understanding of ignition phenomena to allow suitable modelling - Perform systematic studies of the ignition energy of potential ignition sources in order to classify practical ignition sources as weak or strong in

ICHS

Role of hydrogen in launch disasters?28 jan 1986 Shuttle failure of an O-ring4 june 1996 Ariane 5 software problem12 dec 2002Ariane 5 Liquid pp engine design

Advances in Modeling for Safety Applications

Mostly damages in industrial accidents are resulted from explosions of combustible gases and among other combustible gases H2 has unique properties, which makes it one of the most dangerous agent.Thus we are going to speak here about numericalmodeling of possible accidents in industry with H2What are the tasks for CFD in safety: there is a need in better understanding andin development of complete modeling procedure with the view:to predict accident progress and consequencesto develop efficient mitigation measuresto provide reliable data base for rules, codes and standardsto support develop

Hydrogen Jet Ignition Experiments and Modeling

Flame Ignition Limits: Ignitable Gas Envelope ConsiderationsThe ignitable gas envelope is importantto establishing separation distances forunintended releases of hydrogen.The extent of the ignitable gas envelopecan be based on several criteria. Which is best for Codes & Standardsdevelopment?For example:Time-averaged H2concentrationfield reveals extent of cloud withintraditional flammability limits (4%2LFLto 75%2RFL).Do traditional (static) flammabilitylimits provide a suitable measure ofignitability in turbulent flowingsystems?

CFD Analysis

CFD is a numerical method to solve the fluid governing equations that can not be solved in analytical form. By means of numerical simulations of potential accident scenarios, CFD can provide relevant data for risk assessment of hydrogen technologies (estimates of accident consequences e.g. pressure and thermal loads of hydrogen explosions and jet fires) CFD can provide a valuable contribution to the engineering design of safer hydrogen infrastructures and technologies

Combustion

Deflagration and ExplosionIndustrial Accident Initial Conditions:Various H2-air mixture compositions (4%2- 75%2Various geometry environmentOpen geometry (external explosions): outside buildings, little influence of partial confinement and obstacles (in containment such as dome area)Partially confined: limitation in space, geometrical limitations (semi-open configurations; near wall, roof; etc)Confined explosions (internal explosions) inside rooms, compartments, pipes, etcVarious congestionHigh: high space blockage by pipework, cabling, repeating obstacles, etcMedium: intermediate level of

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