The numerical study of ignition risk in the event of high-pressure hydrogen leakage presents numerous challenges. The first is to properly simulate the complex multi-dimensional flow, characterized by a hemispherical expanding shock and a contact discontinuity. The second is to accurately resolve the di!usion/reaction interface, which exhibits a very small length scale compared to the jet radius. These challenges were addressed in our previous work (Le Boursicaud et al., Combust. Flame 274, 2025), leading to the development of a reduced-order model capable of e"ciently predicting the risk of self-ignition in the case of high-pressure hydrogen storage leakage for various geometries.

The present work focuses on extending the previously developed model to account for the e!ects of leakage in confined spaces. These modifications include a simple adjustment of the pseudo-1D model to account for shock reflection, as well as the consideration of entropy jumps occurring during the interaction between the reflected shock wave and the di!usion layer. This work is motivated by the potential increase in ignition risk when leaks occur in confined environments, as opposed to the open environments previously considered (Smygalina and Kiverin, Int. J. Hydrog. Energy 47, 2022).

Novelty and Significance Statement: This work extends a reduced-order model for shock-induced ignition of high-pressure hydrogen leaks from open to confined environments, capturing key e!ects such as shock reflection and shock-contact interaction. It enables e"cient assessment of ignition risk in scenarios where full-resolution simulations are computationally prohibitive.