Study On The Effects Of Transverse Jet On Detonation Initiation

The current enhancement technique to achieve the deflagration-to-detonation transition is through the use of solid obstacles.As the solid obstacles have numerous drawbacks,an alternate new method has been approached using a reactive fluidic jet.A detonation system has been designed and built.The experimental setup consists of the fuel and air supply system,flow control system,the data acquisition system,ignition system,the test stands and the detonation channel.Labview program is write to obtain high frequency dynamic data.The control module made by ARM microcontroller to achieve high-precision time control.The processes and mechanisms of the influence of the transverse jet on flame propagation are studied through the experiments and simulations.In numerical simulation.The comparison results of the characteristics of cold crossflow and the obstacle flow showed that the transverse jet have good performance in total pressure loss;The study transient flow structure of jet in a confined space help to understand the structure of fluid obstacle;Using a detailed chemical reaction mechanism to simulate the propagation law of jet/flame.In the experiment,the effects of the parameters such as the time delay of the jet and the position of the jet are studied,and the effect of the cross jet and multiple jets is conducted.The results showed that with the help of the fluidic obstacle,the DDT time can be shortened successfully by 10%-30%.The transverse jet increase turbulences in detonation chamber and induced a lot of vortex structure.Then enhance interactions of vortex with flame,flame surface curls and folds,leading to rapid transition to detonation wave.Due to the single jet is unable to reflect the shock wave,the detonation effect of the jet in front of the detonation chamber is excellent,and the effect is worse in the middle part.When the working condition is double jet,the structure of the vortex can be formed in the region between two jets,the flame appears multi-core structure and develops rapidly to detonation.The results of this study can be used as a reference for the design of DDT enhance device for pulse detonation engine.