The pressure and deflagration to detonation transition(DDT)characteristics of acetylene and oxygen flame were studied in a detonation tube.The pressure history and the flame velocity along the tube were measured with ...The pressure and deflagration to detonation transition(DDT)characteristics of acetylene and oxygen flame were studied in a detonation tube.The pressure history and the flame velocity along the tube were measured with high frequency pressure transducers and ion probes.By analyzing the data recorded in the experiment,the detonation wave pressure,post wave pressure and DDT distance were obtained,together with the effects of the initial pressure varying from 2×10^(4)Pa to 10^(5)Pa,equivalence ration from 0.3 to 1.0,and mixture concentration from 60%to 100%.It was found that the detonation pressure was decreased respectively with the decrease of initial pressure,equivalence ratio and mixture concentration,but the DDT distance was enlarged.The DDT distance was found particularly sensitive to mixture concentration.展开更多
Pulse detonation engine (PDE) is expected for a next-generation propulsion system. PDE is a promising engine that can generates power and thrust by using intermittent detonation. Promotion of deflagration to detonatio...Pulse detonation engine (PDE) is expected for a next-generation propulsion system. PDE is a promising engine that can generates power and thrust by using intermittent detonation. Promotion of deflagration to detonation transition (below DDT) is a key issue to realize this system. PDE has experimentally been investigated, and it was confirmed that detonation tubes with U-shaped bends are useful for fast DDT. However, the mechanism of DDT promotion due to U-bends has not been well clarified. In the present study, the influence of a U-bend on detona-tion wave propagation is researched with computational fluid dynamics (CFD). The numerical results show that detonation wave disappears once near the U-bend inlet and restarts after passing through it. In addition, it was found that the use of the U-bend with small channel width and curvature radius can induce fast DDT.展开更多
文摘The pressure and deflagration to detonation transition(DDT)characteristics of acetylene and oxygen flame were studied in a detonation tube.The pressure history and the flame velocity along the tube were measured with high frequency pressure transducers and ion probes.By analyzing the data recorded in the experiment,the detonation wave pressure,post wave pressure and DDT distance were obtained,together with the effects of the initial pressure varying from 2×10^(4)Pa to 10^(5)Pa,equivalence ration from 0.3 to 1.0,and mixture concentration from 60%to 100%.It was found that the detonation pressure was decreased respectively with the decrease of initial pressure,equivalence ratio and mixture concentration,but the DDT distance was enlarged.The DDT distance was found particularly sensitive to mixture concentration.
文摘Pulse detonation engine (PDE) is expected for a next-generation propulsion system. PDE is a promising engine that can generates power and thrust by using intermittent detonation. Promotion of deflagration to detonation transition (below DDT) is a key issue to realize this system. PDE has experimentally been investigated, and it was confirmed that detonation tubes with U-shaped bends are useful for fast DDT. However, the mechanism of DDT promotion due to U-bends has not been well clarified. In the present study, the influence of a U-bend on detona-tion wave propagation is researched with computational fluid dynamics (CFD). The numerical results show that detonation wave disappears once near the U-bend inlet and restarts after passing through it. In addition, it was found that the use of the U-bend with small channel width and curvature radius can induce fast DDT.
