The effect of vent burst pressure on a vented hydrogen–air deflagration in a 1 m3 vessel

Abstract

A series of experiments are conducted to investigate the effect of vent burst pressure on stoichiometric hydrogen air premixed flame propagation and pressure history in a 1 m 3 rectangular vessel in this paper. Pressure buildup and flame evolution are recorded using piezoelectric pressure transducers and a high-speed camera, respectively. The results show typical pressure peaks of three different mechanisms for all vent burst pressures in the experiments. The first pressure peak, generated by the rupture of the vent cover, increases with the vent failure pressure, with the subsequent outflow inertia of combustion products giving rise to a negative pressure. The second pressure peak results from the constant bulk motion of the flame bubble (the Helmholtz oscillation), and the third is produced by the interaction between the combustion waves and the acoustic waves. The time interval between the first pressure peak and the second pressure transient remained nearly constant. The Helmholtz oscillation always appears as the vent ruptures and its magnitude increases with the vent burst pressure. Furthermore, the lower the vent failure pressure, the longer the Helmholtz oscillation is sustained. The peak of the acoustically enhanced pressure always occurs within several milliseconds of the flame front to nship between the maximum reduced explosion overpressure and the vent burst pressure precisely. Also, it is observed that the maximum lengths of the external flames were found to be nearly identical in all tests, but the average propagation rate of the flame front increases with the vent burst pressure. It is interesting that a phenomenon of intense oscillation of internal flame bubble was observed with the increase of vent burst pressure.

Experimental Studies on the Explosion Behaviors of Premixed Hydrogen–Air Mixtures in a Narrow Channel

“… 64 After breaking the film, the flame promoted the combustion gas to rush out of the channel quickly, and then refluxed quickly, triggering Helmholtz oscillation. 1 , 21 …”

“…It was a dynamic response caused by a sharp change of pressure in the channel . After breaking the film, the flame promoted the combustion gas to rush out of the channel quickly, and then refluxed quickly, triggering Helmholtz oscillation. , …”

“…64 After breaking the film, the flame promoted the combustion gas to rush out of the channel quickly, and then refluxed quickly, triggering Helmholtz oscillation. 1,21 The accelerating flame acted as a piston and generated compression waves in the unreacted gas. 65 A large number of unreacted gas was compressed at the flame front, resulting in a narrow overpressure peak on the scale of the flame width.…”

“…It has been established that many factors affected the explosion characteristics. The common influencing factors included obstacle, , initial turbulence, vent burst pressure, , ignition position, ,, initial pressure, vent area, equivalence ratio, , and so forth. Exploring the impact results of these factors brought a deeper understanding of hydrogen–air explosion.…”

Influence of the opening pressure of explosion‐venting surface on methane deflagration characteristics in municipal sewage confined spaces

“…The results verified that the effect of the burst pressure of the exhaust port was complex and nonlinear. Rui et al 3 studied the effect of the opening pressure of a vent surface on the deflagration characteristics of a hydrogen–air mixture in a container. According to their results, the propagation velocity of the flame‐front outside the container increased with increasing explosion opening pressure.…”