Explosion venting of rich hydrogen-air mixtures in a small cylindrical vessel with two symmetrical vents

Abstract

The safety issues related to explosion venting of hydrogen-air mixtures are significant and deserve more detailed investigations. Vented hydrogen-air explosion has been studied extensively in vessels with a single vent. However, little attention has been paid to the cases with more than one vent. In this paper, experiments about explosion venting of rich hydrogen-air mixtures were conducted in a small cylindrical vessel with two symmetrical vents to investigate the effect of vent area and distribution on the pressure buildup and flame behavior. Experimental results show that venting accelerates the flame front towards the vent but has nearly no effect on the opposite side. The maximum internal overpressure decreases while the maximum external flame length increases with the increase of the vent area. Two pressure peaks can be identified outside the vessel, which correspond to the external explosion and the following gas jet, respectively. Compared with the case of single vent, the use of two vents with same total vent area leads to nearly unchanged maximum internal and external overpressure but much smaller external flame length.

Numerical analysis of the effect of ventilation door on the propagation characteristics of gas explosion shock waves

“…Excessive overpressure will bring serious damage, in order to reduce the damage of the explosion, a large number of scholars have also carried out research on explosion venting.Yu et al [16]studied the effect of different locations of pressure relief ports in a square straight pipe on the shock wave and flame propagation of a gas explosion.Guo et al [17]and Chen et al [18] carried out the effect of the number and location of pressure relief ports on the explosion overpressure using an experimental setup with pressure relief ports, and the results showed that the number and location of pressure relief ports had a limited effect on the explosion pressure.Sun et al [19]studied the effect of indoor upper gas temperature and flame height on the exterior wall surface when the windows were opened at different angles during an indoor fire, and the results showed that when the window opening angle was less than 60°, the indoor upper gas temperature increased and the flame height on the exterior wall surface decreased as the window opening angle increased.Zhao et al [20]studied the effect of pressure relief conditions on flame and overpressure through a set of experimental devices established to simulate the natural gas explosion process in comprehensive pipe gallery, and the results showed that different pressure relief locations and pressure relief intensities have a great influence on the explosion characteristics of comprehensive pipe gallery.Wang et al [21] studied the damaging factors of gas explosion shock wave on mine ventilation system and the attenuation law of explosion wave in roadway space, and designed a ventilation door with automatic pressure relief and reset under overpressure to reduce the destructive effect of explosion shock wave.Sun et al [22] conducted a study on the effectiveness of ventilation blast doors in isolating gas explosion shock waves and the results showed that after using ventilation blast doors, the maximum gas explosion overpressure was significantly reduced by 21% and the shock waves at the rear of the explosion pipeline were significantly suppressed.…”

Experimental Study of External Flame Evolution and Temperature Characteristics after a Methane Explosion in a Rectangular Chamber

“…This indicates the higher responsibility of the nonlinear extrapolation approach compared with the linear one. By using a cylindrical vessel, Guo et al 29 investigated the influence of the vent areas on the pressure and external flames, showing an increase in the pressure peak and flame length with an enlarged vent area. Mercx et al 30 studied the external explosion hazard during venting and determined the maximum external pressure after rear ignition.…”

Dispersion analysis of hydrogen released from a fuel cell electric vehicles with ventilations

“…The number of the vents is crucial to the ventilation. The compartment with two vents were proposed to enhance the efficiency of ventilation [14][15][16][17][18]. Saikili et.…”