摘要
在装有对开式泄爆板的透明爆燃腔体内,用试验方法研究了甲烷/空气预混气体爆燃过程中的爆燃压力、火焰传播速度及泄爆板转动规律。结果表明:在对开式泄爆条件下,与无障碍物的工况相比,随障碍物数量增多或当量比从0.7增大到1.0,火焰传播速度、爆燃过程中的最大压力和泄爆板开启速度越来越大;当量比越接近1.0,泄爆过程中压力峰值产生的时间越提前;由于对开式泄爆板的瞬态泄压作用,压力曲线波峰附近出现"凹陷"现象。此外,在对开式泄爆容器的设计过程中,应尽可能减少容器中障碍物的数量,以降低爆燃过程中的压力峰值。
This paper aims at investigating the methane/air deflagration characteristics in a confined space under the split ventilating condition. As is known, it is one of the most likely accidental scenarios in premixing the chemicals for mixture deflagration in the chemical processing industries. It is just for this end that we have made an experimental investigation of a pair of split ventilating plates in a transparent explosion chamber with the purpose to explore the deflagration overpressure, the burning flame speed, and the rotating regularity of the ventilating plates in the premixed methane/air deflagration process. In our experiments, we have observed and monitored the dynamic overpressure generated by the methane-air premixed deflagration material at 5 kHz by using a PR-23-type pressure transmitter. At the same time, we have also traced and captured the images of the propagating flames by means of a high-speed digital camera operated at 2 000 frames per second. The experimental results we have gained show that if the number of obstacles were increasing, or if the equivalent concentration of methane/air premixed gases tended to increase from 0.7 to 1.0, the flame speed, the magnitude of the peak overpressure of methane/air deflagration, and the rotating speed of the split ventilating plates would be getting higher under the said ventilating conditions, as compared with the experimental data in case of obstacle-free condition. It can thus be seen that it would be possible to find that the turbulence intensity may have significant effects on the deflagration characteristics, such as the flame propagation speed and deflagration overpressure. What is more, it can also be found that the equivalent concentration of methane/air premixed gases should be closer to 1.0, on the condition that the time of the peak pressure may come earlier during the ventilating process. Furthermore, the results of our experiments also demonstrate that the overpressure curves turned to be ＂depressed＂ in the whole process of the deflagration because of the instantaneous pressure released by the ventilating plate. As a result, it would be possible to minimize the risk associated with the methane/air deflagration if it would be possible to predict the number of obstacles. In addition, it is also necessary to take full account of the effects of the premixed gases concentration on the time needed to open the split ventilating plates. Thus, it can be concluded that such results tend to play a significant role in designing and operating the ventilation facilities in the chemical processing industries.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第3期10-14,共5页
Journal of Safety and Environment
基金
河南理工大学博士基金项目(B2010-41)
河南理工大学热能工程重点资助项目(509927)
关键词
安全工程
泄爆
瓦斯爆燃
火焰传播
safety engineering
explosion venting
gas deflagration
flame propagation
