Numerical study of hydrogen leakage, diffusion and explosion in the parking garage under closed and natural ventilation conditions

This study employed the CFD to evaluate the characteristics of hydrogen leakage, dispersion and explosion via activation of Thermally Activated Pressure Relief Devices (TPRDs) when HFCVs parking in a confined or ventilated parking space. The impact of varying leak diameters (2, 3, and 4 mm), natural ventilation and vehicle count on the formation of flammable gas clouds, their concentration distribution, and the generation of overpressure after the explosion were explored. The results showed that larger TPRD diameters resulted in more extensive clouds of highly concentrated hydrogen which dispersed more rapidly. Ventilation decreased both the volume and concentration of flammable clouds. In addition, large leak diameters resulted in larger pressure peaks after the explosion, in contrast, the danger was minimized in the single-vehicle case. Additionally, pressure peaks were higher in the parking lot's corners. This study offers theoretical support for safely parking HFCVs in confined spaces.