狭缝内乙烯/氧气预混气体爆轰几何极限的实验

Experiment on geometrical limits of gaseous detonation of ethylene/oxygen mixtures in narrow gaps

为研究狭缝内爆轰波传播极限,实验得到了不同初始压力（0.004~0.04MPa）下化学恰当比的乙烯/氧气预混气体在狭缝高度为1.0~4.0mm狭缝内的爆轰性能.采用烟膜板记录爆轰波运行轨迹,高速摄影捕捉火焰面.结果表明：狭缝高度越小,爆轰极限对应的临界初始压力越高.对于近极限条件内不稳定爆轰传播模式,包括＂结巴＂爆轰和驰振爆轰,其对应的初始压力范围随着狭缝高度的降低而变宽.考虑初始和边界条件,将水力直径与胞格宽度之比作为合理的爆轰敏感性参数描述预混气体爆轰特性,得出在不同狭缝通道内爆轰极限范围为,即该比值在0.326~0.403之间.

To study the detonation limits of detonation,the gaseous detonation of stoichiometric ethylene/oxygen mixtures through narrow gaps with height of 1.0-4.0mm was experimentally studied by varying initial pressure of 0.004-0.04 MPa.The soot film was utilized to record the cellular structure of detonation,and the high-speed cinematography was used to capture the flame.Results show that the smaller narrow gap height means the higher critical initial pressure for limits of detonation propagation.For unsteady detonation propagation modes near the detonation limits,including＂stuttering＂detonation and galloping detonation,the corresponding range of initial pressure becomes wider as the height of gap decreases.By considering both initial and boundary conditions,the ratio of hydraulic diameter to cellular width is found to be an appropriate sensitivity parameter to characterize the mixture.The range of this ratio for defining detonation limits in different narrow gap sizes is0.326-0.403.