可燃气体混合物燃烧转爆轰判据对比分析

Analysis of the Onset of Detonation in the DDT Process for Combustible Mixture

基于气相爆轰实验中到爆轰时刻不同判据之间的比较,利用数字高速摄影相机,在激波管中开展化学计量比的乙炔-氧气混合气体的燃烧转爆轰实验,对比了6种不同的判据判读到爆轰时刻数据之间的差异。对比分析表明,采用波阵面火焰发光强度和波阵面轨迹作为乙炔-氧气混合气体到爆轰时刻的判据,能够更精确地获得到爆轰时间和到爆轰距离。不同判读数据之间的差异较大,主要原因是在燃烧转爆轰过程中发生局部爆炸,对压力和波速的走时产生较大的影响,导致了判读到爆轰时刻的误差。

For comparison with several methods used to define the location of the onset of detonation, several of experiments were performed to study on the deflagration to detonation transition （DDT） for premixed C2 H2 ＋2. 5O2 mixture in a shock tube. A high-speed digital camera was used to track the velocities of flame, shock, or detonation wave. In this work, six methods were used to define the location of the onset of detonation,and six different results of the DDT run-up distance （LDDT） and the time of the detonation onset （tDDT） were obtained. It is found that the methods based on the flame emission radiation and the growth trajectory of flame, shock,or detonation wave can accurately define tooT and LDDT. The onset of detonation defined by the other methods based on the speed of detonation wave might result in some error or underestimated values due to the localized explosion taking place just prior to the generation of detonation.