点火位置对氢气-空气预混气体泄爆过程的影响

Effect of ignition locations on vented explosion of premixed hydrogen-air mixtures

利用高速纹影和压力测试系统对不同点火位置及不同破膜压力条件下氢气-空气预混气的泄爆特性进行研究。研究结果表明:在所有情况下,中心点火时火焰传播速率和面积最大,产生了最大的内部压力峰值,尾端点火时火焰传播速率和面积次之,产生的内部压力峰值也次之;前端点火时火焰传播速率和面积均最小,产生了最小的内部压力峰值。前端点火时,容器内部压力出现了3个明显的压力峰值,中心和尾端点火时,只能观察到第1个和第3个压力峰值。并且,随着破膜压力的增加,中心和尾端点火时,火焰面积均增大,产生的内部压力峰值均增大。在前端点火的条件下出现了声学振荡的现象,对内部压力产生了显著的影响。

In this work experiments were carried out to investigate the effect of ignition locations and vent burst pressures on the pressure profile and the flame propagation during explosion venting of hydrogen-air mixtures.The results indicate that,in all the cases,the central ignition leads to the largest flame areas,the highest flame propagation velocities and peak pressures peak pressures;compared with that of the central ignition,the effect of the rear ignition on the flame propagation velocity,the flame areas and the peak pressures is reduced,while the front ignition results in the smallest flame areas,the lowest flame propagation velocity and peak pressures.For the front ignition,the pressure profile exhibits three peak pressures which correspond to the following three successive stages,but for the central and rear ignition,only the first and the third peak pressure can be found.Furthermore,both the peak pressures and the flame areas increase with the bursting pressure.Overpressure measurements made inside the chamber show clearly that the acoustic oscillation occurs and the internal pressures were influenced by the external explosion.