Explosion Mechanics in Relation to Hydrogen

Hydrogen has been commonly used for years and has a range of properties that are now well understood by the broader industry. Some of those properties, such as flammability and reactivity, mean that hydrogen displays some unique characteristics with respect to explosions. Whilst hydrogen is now familiar to many, some of its properties and how they relate to explosion outcomes, are less commonly understood.

This submission will examine the general topic of flammable gas explosion mechanics at a high level. The discussion will cover topics such as:

• the factors that contribute to explosions, and
• what elements increase the severity of explosions,
• with particular focus on confinement, congestion and turbulence.

Following the discussion on general explosion mechanics, the submission will relate these specifically to hydrogen and the properties of hydrogen that can lead to increased explosion severity.

Finally, the submission will briefly discuss results that have been observed for simulations of the unique case of hydrogen/oxygen explosions within vessels. These CFD simulations have been run for a number of projects to simulate the formation of a flammable atmosphere in an oxygen vessel, typically due to a leaking electrolyser stack membrane allowing a hydrogen to leak into an oxygen/water separator. Whilst the results are based on simulation only, they have provided insight into the potential consequences of these events and the means to practicably mitigate them.