Abstract: Abstract: In the event of an emergency, a hydrogen fuel cell vehicle will actively discharge hydrogen. At present, research is needed on the safety of emergency hydrogen discharge from hydrogen fuel cell vehicles. To study the characteristics of emergency discharge of hydrogen fuel cell vehicles in open space and the influence of wind speed on them, Fluent software was used to establish a model of hydrogen fuel cell vehicles in open space, and the law of hydrogen diffusion and the development of hydrogen combustible areas and warning areas were analyzed. When hydrogen fuel cell vehicles is urgently deflated in the open space, the larger the wind speed facing the wind, the smaller the maximum volume and stable volume of the hydrogen explosion able cloud, and the less time it takes to reach the maximum volume and stable volume. The size of the hydrogen level warning area and the positive warning area decreases with the increase of the wind speed, and the shape is changed by the influence of the wind speed; after the release is stopped, the combustible gas will quickly spread and disappear. This conclusion can provide a basis for the safety verification of emergency hydrogen discharge by hydrogen fuel cell vehicles.

Key words: hydrogen fuel cell vehicle, hydrogen discharge, gas diffusion, numerical simulation