Abstract:

To measure the key free radicals of the gasoline-air explosion in long-narrow confined space accurately, which is important to the accurate analysis of the explosion flow field and the flame propagation, an experimental study on the gasoline-air mixture explosion in a long-narrow confined space is designed based on the planar laser induced fluorescence system (PLIF),and the experiments in different conditions of the gasoline-air explosion in long-narrow confined space are carried out. The concentration distributions of the OH radical of those are obtained. The results of experiments show that the concentration of OH radical rises and then descends among the gasoline concentrations of 1.1%—2.4%(volume fraction); the concentration of OH radical rises steadily along with the development of flame propagation, which means the explosion is strengthen; the distributions of the OH radical are different in different explosion stages, which means the combustion reaction area in different explosion stages differs a lot; there is a "isolation belt" between the flame and the wall, which is the result of the slowing of the flame propagation caused by the concentration increase of unburned gasoline. The main innovation is to solve the transient measurement of free radical distribution in unsteady premixed combustion by designing the timing control subsystem.

Key words: gasoline-air mixture explosion, PLIF, OH radical, reaction kinetics, radical, explosions

摘要：

为了精确测量狭长受限空间油气爆炸过程中的关键自由基团，从而实现对其爆炸流场、火焰传播的精确分析，基于先进的平面激光诱导荧光测量技术（PLIF），设计构建了油气爆炸PLIF测量系统，开展了不同工况下狭长受限空间汽油-空气混合气爆炸实验研究，获得了该爆炸中间基团OH基的浓度分布。实验结果表明，1.1%~2.4%（体积分数）油气浓度之间，OH基浓度先增大后减小；随火焰的传播发展，OH基浓度不断变大，表明爆炸不断强化；爆燃不同时期OH基分布情况不同，表明不同爆燃阶段的燃烧反应区域有较大差异；爆燃前期火焰与壁面之间有“隔离带”，是由未燃气浓度增大导致火焰传播变慢的结果。主要创新点在于通过设计时序控制子系统，解决了非稳态预混燃烧中自由基分布瞬态测量。

关键词: 油气爆炸, PLIF, OH基, 反应动力学, 自由基, 爆炸