气相爆轰波反应区结构的平面激光诱导荧光测量

基于平面激光诱导荧光(PLIF)技术对2H2 O2 10Ar的预混气体爆轰波反应区结构进行实验研究.采用高浓度的氩稀释有利于减小爆轰化学反应自发辐射光对OH荧光的影响.合理设置PLIF系统、爆轰波和ICCD之间的同步控制触发延时,得到爆轰波阵面附近的OH荧光分布图像.结果表明:诱导激波后反应阵面不是平面且不稳定.荧光图像上能清晰地看到类似拱顶石的结构,它位于两马赫杆之间,以入射激波、剪切层和反应阵面为边界.无论是在马赫杆后还是在入射激波后,OH浓度分布在诱导区末端急剧增加至最大值.随着离开反应阵面的距离增加,OH浓度快速减小.由于爆轰模式和激光片光方向的影响,从PLIF图像上测得的横波间距值较离散,均小于胞格宽度.

STUDY ON REACTION ZONE STRUCTURE OF GASEOUS DETONATION WAVE BY PLANAR LASER INDUCED FLUORESCENCE TECHNIQUE

The reaction zone structure of gaseous detonation wave in stoichiometric hydrogen-oxygen mixture diluted with 76.92% argon was directly observed by planar laser induced fluorescence technique.Such high argon dilution was employed to degenerate natural fluorescence mainly caused by detonation chemical reaction. The synchronization of the PLIF system,the detonation wave and ICCD were carefully adjusted.The images of OH fluorescence distribution in the wake of the detonation front were obtained.These images show that the reaction zone is spatially and temporally changeable and the reaction front is not planar and is very unstable. The distinct keystone-like structure,with the incident shock,the shear layers and the reaction front as its boundaries,can be clearly observed.Whether the OH concentration is behind the Mach stem or the incident shock,it abruptly increases to the maximum value at the end of the induction zone and then decreases with increase of the distance from the reaction front.Due to the effects of the detonation mode and laser sheet direction,the transverse wave spacing measured from the PLIF images exhibits a relatively large scatter,and assumes a value smaller than the cell width.