初始压力对爆轰波在管道内传播的影响

Effect of initial pressure on propagation of detonation wave in round tube

建立爆轰管道研究不同初始压力下爆轰波在管道内传播规律.选用CH4+2O2气体,采用光纤探针测量爆轰波在管道内的传播速度,采用烟迹法记录爆轰波胞格结构.结果表明:爆轰波在管道内传播时出现5种不同传播模式,分别为稳态式、快速波动式、结巴式、驰振式与失效模式.在稳态传播模式下,爆轰波局部速度波动很小且平均速度接近理论爆轰CJ速度,并呈现多头胞格结构.随着初始压力的降低,爆轰波局部速度波动增加且其平均速度产生衰减.在驰振式爆轰解耦处,爆轰波胞格结构消失,过载爆轰时,重新形成胞格结构.进一步降低初始压力至爆轰失效时,则无胞格结构.

Detonation tube was built to investigate the effect of initial pressure on the propagation of detonation wave in round tube.The premixed gas of CH4＋2O2 was selected as experimental gas. Optical fiber probe was used to measure the local velocity of detonation wave.Smoked foils were used to register the cellular structure of detonation wave in tubes.The experimental results show that there are five distinct modes during the propagation of detonation wave in tubes,which are stable mode,rapid fluctuation mode,stuttering mode,galloping mode and failure mode.Under the mode of stable detonation,the fluctuations of the local velocity of detonation wave are generally small and the averaged velocity of detonation wave is close to the theoretical CJ value.The detonation wave has multi-headed cellular structure.With decreasing of the initial pressure,the fluctuations of the local velocity of detonation wave increase,and the averaged velocity of detonation wave decreases.For the galloping detonation,at the decoupled position,cellular structure disappears.Cellular structure forms again when overdriven detonation occurs.If the initial pressure is further decreased till the detonation failure,no cellular structure is observed.