Hazard analysis on tunnel hydrogen jet fire based on CFD simulation of temperature field and concentration field

•Hydrogen jet fire in tunnel may cause explosion accident due to fuel accumulation.•Excessive leak rate will inhibit further diffusion of hydrogen in the tunnel.•Adequate ventilation can effectively inhibit hydrogen accumulation and diffusion.•Larger tunnel cross-sectional area has more inhibitory effect on hydrogen diffusion.•Longitudinal ventilation may lead to the drop of height of high-temperature layer.