Hydrogen leakage in underground garages: Impact of leakage locations on gas diffusion and safety considerations

Hydrogen leakage in confined spaces is a significant safety hazard for hydrogen energy applications, as it can lead to the formation of highly concentrated gas clouds, elevating the potential for fire and explosion incidents. This paper develops a study on hydrogen leakage in a confined garage and establishes a 1/10 downscaled experimental model to investigate gas diffusion behavior and spatial-temporal distribution characteristics resulting from leakage at different locations. Through a combination of experimental and numerical simulation methods, the study reveals that the highest hydrogen concentration occurs directly above the leak source at all three locations (center, wall, and corner) when the leak is upward. Furthermore, the concentration distribution correlates positively with the length of the dispersion path from the ceiling center above the leak source to the measuring point. The presence of constraints around the vehicle's parking location leads to a reduction in hydrogen spread due to leakage. Specifically, the volume of the hydrogen overrun area is greatest for leaks occurring in the center of the garage and smallest when leaks occur in the corners. The findings of this research offer theoretical insights for the early warning design of underground garages for hydrogen energy vehicles.