The effect of hydrogen leakage positions and leak flow rate on its dispersion in a small fuel cell bus

Studies on hydrogen leakage mainly have focused on the influences of the leakage locations and geometrical configurations on the distribution of hydrogen in various spaces. In this study, a simplified model was developed to examine the diffusion of the hydrogen leaked into a small fuel cell bus with seats. The impact of leakage positions and leak flow rate on the dispersion of hydrogen in a cuboid ventilation space (with dimensions L x W x H = 5 m x 2 m x 2 m) was investigated, and concentrations of hydrogen in the vicinity of the corner at the ceiling were of particular interest. It was shown the peak average concentration at the ceiling increased with increasing the leak flow rate. However, the duration from the appearance to the disappearance of the combustible hydrogen-air mixture decreased with the increase of the leak flow rate. This study highlights the importance of leakage positions and demonstrates that the dispersion of hydrogen is faster for leakage in the horizontal direction. The proposed approach is useful for improving the design of the arrangement of hydrogen storage tanks to eliminate consequent accidents or minimize the harmful impacts during an accident.