Study of hydrogen jet fire behavior in longitudinal ventilated tunnel

The effect of longitudinal ventilation on hydrogen jet fires was investigated in tunnel. The extended flame length, temperature, and thermal radiation flux were measured for nozzle diameters (1 similar to 5.12 mm), tilt angles (30-60 degrees) and pressures (1-4 MPa). The results indicate that the longitudinal wind speed has a suppressive effect on the extended flame length on the ground. The extended flame length on the ground decreases with increasing wind speed. Longitudinal ventilation also has a suppressive effect on the gas temperature around the flame, and the maximum temperature difference decreases with increasing wind speed. Based on the geometric model of the extended flame, a fitted relationship between the dimensionless extended flame length and the longitudinal wind speed was established. Additionally, a fitted relationship between the dimensionless peak flame temperature and the normalized position was also proposed.