用烟迹法研究爆燃向爆震的转捩

为能直观了解由爆燃到爆震的转捩过程(简称DDT)中激波的变化过程,在60mm×60mm×2000mm方爆震管的侧面设置了60mm×1380mm的窗口来获得爆震波的烟迹图,分别用乙炔(C₂H₂)和空气、氢气(H₂)和空气混合物进行了单次爆震性能研究.利用安装在同一截面上的压力传感器与离子探针同时测得DDT位置段爆震管内的压力分布、火焰传播速度和方向.试验结果表明:①烟迹法是研究DDT更为直接和有效的手段之一;②在本试验条件下,观察到DDT过程中过爆只会出现一次,但从过爆衰减至正常C-J爆震波的过程中存在多次多点爆炸的迹象;③初始条件相同的情况下,乙炔的胞格尺寸小于氢气的胞格尺寸. 

Experimental study on DDT using soot records

In order to understand the process of shock movement,soot records were obtained by arranging a window of 60 mm×1 380 mm laterally onto a square donation tube.A series of single detonation experiments were conducted to study the performance of C₂H₂/air and H₂/air mixtures in square detonation tube.The pressure transducers and ion-probes were utilized to measure the pressure and velocity in the tube,respectively.The results indicate that : ① Soot records is one of direct and effective means;② Overdriven detonation appears only once and several blasts appear in DDT(Deflagration to detonation transition);③ The dimension of acetylene is less than that of hydrogen under the same initial condition.