Impacts of wind conditions on hydrogen leakage during refilling hydrogen-powered vehicles

Although hydrogen leakage at hydrogen refueling stations has been a concern, less efforts have been devoted to hydrogen leakage during the refueling of hydrogen-powered vehicles. In this study, hydrogen leakage and dilution from the hydrogen dispenser during the refueling of hydrogen-powered vehicles were numerically investigated under different wind configurations. The shape, size, and distribution of flammable gas clouds (FGC) during the leakage and dilution processes were analyzed. The results showed that the presence of hydrogen-powered vehicles resulted in irregular FGC shapes. Greater wind speeds (v_wv) were associated with longer FGC propagation distances. At v_wv = 2 m·s⁻¹ and 10 m·s⁻¹, the FGC lengths at the end of the leakage were 7.9 m and 20.4 m, respectively. Under downwind conditions, higher wind speeds corresponded to lower FGC heights. The FGC height was larger under upwind conditions and was slightly affected by the magnitude of the wind speed. In the dilution process, the existence of a region with a high hydrogen concentration led to the FGC volume first increasing and then gradually decreasing. Wind promoted the mixing of hydrogen and air, accelerated FGC dilution, inhibited hydrogen uplifting, and augmented the horizontal movement of the FGC. At higher wind speeds, the low-altitude FGC movements could induce potential safety hazards.