Influence of vent size on characteristics of hydrogen explosion venting: Experimental investigation and numerical simulation

Several serious leakages and explosions occurred during the rapid development of hydrogen, resulting in devastating accidental disasters. To further investigate the influence law and mechanism of hydrogen explosion venting. Experimental and simulation research was carried out to investigate the effect of the vent size on the explosion pressure, the flow field microstructure, the dynamic evolution and the temperature distribution of the venting flame. The under-expanded jet structure (Mach disk) is formed when vent diameter are 60 mm and 70 mm, and the temperature field presents a continuous fracture distribution. The increase of the vent size promotes the increase of the venting efficiency, therefore the P_max gradual decreases. However, it also promotes the increase of the amount of external unburned hydrogen and the maximum propagation distance of the venting flame. The decrease of the vent size promotes the frequency of airflow backflow oscillations increase. The research result can provide theoretical basis and technical support for realizing efficient hydrogen explosion protection and promoting the rapid development of hydrogen energy.