A comprehensive guide to Best Practice Guidelines (BPG) in numerical simulations for Fuel Cells and Hydrogen applications has been one of the main outputs of the SUSANA project. These BPG focus on the practical needs of engineers in consultancies and industry undertaking Computational Fluid Dynamics (CFD) simulations or evaluating CFD simulation results in support of hazard/risk assessments of hydrogen facilities, and the needs of regulatory authorities. This contribution presents the BPG document and the BPG application through a series of CFD benchmarking examples.
Socio-economic analysis and quantitative risk assessment methodology for safety design of onboard storage systems
Catastrophic rupture of onboard hydrogen storage in a fire is a safety concern. Different passive, e.g. fireproofing materials, the thermally activated pressure relief device (TPRD), and active, e.g. initiation of TPRD by fire sensors, safety systems are being developed to reduce hazards from and associated risks of high-pressure hydrogen storage tank rupture in a fire. The probability of such low-frequency highconsequences event is a function of fire resistance rating (FRR), i.e. the time before tank without TPRD ruptures in a fire, the probability of TPRD failure, etc.
For the emerging hydrogen-powered vehicles, the safety concern is one of the most important barriers for their further development and commercialization. The safety of commercial natural gas vehicles has been well accepted and the total number of natural gas vehicles operating worldwide was approximately 23 million by November 2016. Hydrogen vehicles would be more acceptable for the general public if their safety is comparable to that of commercialized CNG vehicles.
Vehicular use of hydrogen is the first attempt to apply hydrogen energy in consumers’ environment in large scale, though hydrogen has been widely used in industrial field for over one hundred years. The increasing number of hydrogen fuel cell vehicles has raised safety concerns in both public authorities and private bodies such as fire services and insurance companies. This paper analyzes typical accident progressions of hydrogen fuel cell vehicles in a road accident.
China has plenty of renewable energy like wind power and solar energy especially in the northwest part of the country. Due to the volatile and intermittent characters of the green powers, high penetration level of renewable resources could arise grid stabilization problem. Therefore electricity storage is considered as a solution and hydrogen energy storage is proposed. Instead of storing the electricity directly, it converts electricity into hydrogen and the energy in hydrogen will be released as needed from gas to electricity and heat.
A methodology for explosion and fire risk analyses in enclosed rooms is presented. The objectives of this analysis are to accurately predict the risks associated with hydrogen leaks in maritime applications and to use the approach to provide decision support regarding design and risk-prevention and riskmitigating measures. The methodology uses CFD tools and simpler consequence models for ventilation, dispersion and explosion scenarios, as well as updated frequency for leaks and ignition.
Nomograms for assessment of hazard distances from a blast wave, generated by a catastrophic rupture of stand-alone (stationary) and onboard compressed hydrogen cylinder in a fire are presented. The nomograms are easy to use hydrogen safety engineering tools. They were built using the validated and recently published analytical model. Two types of nomograms were developed – one for use by first responders and another for hydrogen safety engineers.
According to the Global technical regulation on hydrogen and fuel cell vehicles (FCV), fuel cell discharge system at the vehicle exhaust system`s point of discharge, the hydrogen concentration level shall not exceed 4 % average by volume during any moving three-second time interval during normal operation including start-up and shut down . FC stack need to washout by the concentrated hydrogen as the purge gas and how to exhaust gas without exceeding 4 % is the most concerns. Also how to measure hydrogen pulse of millisecond in exhaust is also the rising up issue.
Portable H2 sensor was made by using mass spectrometer for the outside monitoring experiment: the leak test, the replacement test of gas pipe line, the combustion test, the explosion experiment, the H2 diffusion experiment and the recent issue of the exhaust gas of Fuel Cell Vehicle. In order to check the real time concentration of H2 in various conditions, even in the highly humid condition, the system volume of the sampling route was minimized with attaching the humidifier.
Influence of initial pressure in hydrogen/air flame acceleration during severe accident in Nuclear Power Plant
Flame acceleration (FA) and explosion of hydrogen/air mixtures remain key issues for severe accident management in nuclear power plants. Empirical criteria were developed in the early 2000s by Dorofeev and colleagues, providing effective tools to discern possible FA or DDT (Deflagration-toDetonation Transition) scenarios. A large experimental database, composed mainly of middle-scale experiments in obstacle-laden ducts at atmospheric pressure condition, has been used to validate these criteria.