Numerical simulation of hydrogen leakage and accident consequence of hydrogen explosion in compact confined hydrogen-electric coupling systems

Previous hydrogen safety research typically focuses on scenarios such as hydrogen refueling stations, garages, and so on, which are usually located in open, semi-open spaces and simply confined spaces. However, the diffusion characteristics of hydrogen leakage and the consequences of accidents in hydrogen-electric coupling system (HECS) within a compact confined space with complex equipment layouts remain unclear. This study evaluates the characteristics of hydrogen leakage, diffusion, and explosion in HECS within a compact confined space based on numerical simulation. The effects of leakage positions, leakage diameters, container sizes, and ventilation outlet layouts on the hydrogen leakage and diffusion characteristics are explored. Furthermore, this study investigates the effects of container size and ventilation outlet positions on reducing explosion hazards, and ultimately determines the optimal container size and ventilation outlet arrangement. The results show that compared to a spacious space, when hydrogen leaks in a congested space, it is blocked by obstacles and accumulates locally. Furthermore, the most severe consequence of hydrogen explosion occurs due to large-scale leakage in the solid-state hydrogen storage system, resulting in an overpressure of 2630 kPa and a damage radius of 25 m. Increasing the container size and incorporating forced ventilation systems effectively reduce the hydrogen concentration and mitigate the consequences of hydrogen explosions. Compared to placing the ventilation outlet on the sidewall, placing it on the top results in higher ventilation efficiency and better safety protection. This study provides valuable insights into the choice of container and the layout of ventilation systems in HECS within the compact confined space.