Modelling liquid hydrogen release and spread on water

Consequence modelling of high potential risks of usage and transportation of cryogenic liquids yet requires substantial improvements. Among the cryogenics, liquid hydrogen (LH2) needs especial treatments and a comprehensive understanding of spill and spread of liquid and dispersion of vapor. Even though many of recent works have shed lights on various incidents such as spread, dispersion and explosion of the liquid over land, less focus was given on spill and spread of LH2 onto water.

Validation of a 3d multiphase-multicomponent CFD model for accidental liquid and gaseous hydrogen releases

As hydrogen-air mixtures are flammable in a wide range of concentrations and the minimum ignition energy is low compared to hydrocarbon fuels, the safe handling of hydrogen is of utmost importance. Additional hazards may arise with the inadvertent spill of liquid hydrogen. An accidental release of LH2 leads to a formation of a cryogenic pool, a dynamic vaporization process, and consequently a dispersion of gaseous hydrogen into the environment. Several LH2 release experiments as well as modeling approaches address this phenomenology.

Modeling of hydrogen pressurization and extraction in cryogenic pressure vessels due to vacuum insulation failure

We have analyzed vacuum insulation failure in an automotive cryogenic pressure vessel (also known as cryo-compressed vessel) storing hydrogen (H2). Vacuum insulation failure increases heat transfer into cryogenic vessels by about a factor of 100, potentially leading to rapid pressurization and venting to avoid exceeding maximum allowable working pressure (MAWP). H2 release to the environment may be dangerous if the vehicle is located in a closed space (e.g. a garage or tunnel) at the moment of insulation failure.

Mixing and warming of cryogenic hydrogen releases

Laboratory measurements were made on the concentration and temperature fields of cryogenic hydrogen jets. Images of spontaneous Raman scattering from a pulsed planar laser sheet were used to measure the concentration and temperature fields from varied releases. Jets with up to 5 bar pressure, with near-liquid temperatures at the release point, were characterized in this work. This data is relevant for characterizing unintended leaks from piping connected to cryogenic hydrogen storage tanks, such as might be encountered at a hydrogen fuel cell vehicle fueling station.

Empirical profiling of cold hydrogen plumes formed from venting of LH2 storage vessels

Liquid hydrogen (LH2) storage is a viable approach to assuring sufficient hydrogen capacity at commercial fuelling stations. Presently, LH2 is produced at remote facilities and then transported to the end-use site by road vehicles (i.e., LH2 tanker trucks). Venting of hydrogen to depressurize the transport storage tank is a routine part of the LH2 delivery process. However, the behaviour of cold hydrogen plumes has not been well characterized because empirical field data are essentially non-existent.

Thermal radiation from cryogenic hydrogen jet fires

The thermal hazards from ignited under-expanded cryogenic releases are not yet fully understood and reliable predictive tools are missing. This study aims at validation of a CFD model to simulate flame length and radiative heat flux for cryogenic hydrogen jet fires. The simulation results are compared against the experimental data by Sandia National Laboratories on cryogenic hydrogen fires from storage with pressure up to 5 bar abs and temperature in the range 48-82 K. The release source is modelled using the Ulster’s notional nozzle theory. The problem is considered as steady-state.

Numerical modelling of hazards of hydrogen storage

For the general public to use hydrogen as a vehicle fuel, they must be able to handle hydrogen with the same degree of confidence as conventional liquid and gaseous fuels. The hazards associated with jet releases from accidental leaks in a vehicle-refuelling environment must be considered if hydrogen is stored and used as a high-pressure gas since a jet release can result in a fire or explosion. This paper describes the work done by us in modelling some of the consequences of accidental releases of hydrogen, implemented in our Fire Explosion Release Dispersion (FRED) software.

A safety assessment of hydrogen supply piping system by use of FDS

At least once, air filling a piping from main hydrogen pipe line to an individual home end should be replaced with hydrogen gas to use the gas in the home. Special attention is required to complete the replacing operation safely, because air and supplied hydrogen may generate flammable/explosive gas mixture in the piping. The most probable method to fulfill the task is that, at first an inert gas is used to purge air from the piping, then hydrogen will be supplied into the piping.

Pressure effects of an ignited release from onboard storage in a garage with a single vent

This work is driven by the need to understand the hazards resulting from the rapid ignited release of hydrogen from onboard storage tanks through a thermally activated pressure relief device (TPRD) inside a garage-like enclosure with low natural ventilation i.e. the consequences of a jet fire which has been immediately ignited. The resultant overpressure is of particular interest. Previous work [1] focused on an unignited release in a garage with minimum ventilation.

Compatibility and suitability of existing steel pipelines for transport of hydrogen and hydrogen-natural gas blends

Hydrogen is being considered as a pathway to decarbonize large energy systems and for utility-scale energy storage. As these applications grow, transportation infrastructure that can accommodate large quantities of hydrogen will be needed. Many millions of tons of hydrogen are already consumed annually, some of which is transported in dedicated hydrogen pipelines. The materials and operation of these hydrogen pipeline systems, however, are managed with more constraints than a conventional natural gas pipeline.

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