Research On Detonation Initiation By Hot Jet For A PDE With Rotary-tube Valve

Compared with other kinds of PDE, a new PDE model that uses the cylindrical rotary valve andjet-flame of the pilot-burner ignition is more efficient. The detonation initiation is the key technologyof Pulse Detonation Engine (PDE). In order to initiate in a short distance and low resistance, thepresent research was concerned with the method of combining numerical simulation with experiment.Three new technology of flame jet detonation initiation were investigated in the single tube andmulti-tube PDE systems. The results attained from the research including:1. A prototype PDE based on cylindrical rotary valve and jet-flame of pilot-burner ignition is designedin this paper by analyzing the principle of the PDE with Rotary-tube Valve. The six Pulsed detonationchambers were arranged in a sector-annular configuration on a318mm circle. Each tube was82mmequivalent diameter with a length of1550mm as measured from the downstream face of the fuel-airmixing element to the tube exit.2. Through the numerical simulation, the discipline of flow field in jet flow generator outlet and flamepropagation were analyzed, and found that jet flame could invent the favorable conditions for ignitingthe mix gas. Through the research in discipline of flame and shock wave propagation, we could foundthat jet flame initiation could invent detonation wave, and create a foundation for investigation insingle tube PDE.The jet flame created by jet flame generator successfully ignited the mix gas in thePDE tube, and created the detonation wave; Through the research of a certain jet generator lengthfound that the diameter of flame jet orifice slightly affects detonation initiation sensitivity, and theconfigurations of flame sub-chamber are slightly effect on deflagration-to-detonation transition (DDT)distance, but the DDT time decreases while the length of the flame sub-chamber increases; When thejet tube length increases to a certain value, increasing the length of jet tube will not continue toshorten DDT time.3. A prototype PDE based on cylindrical rotary valve and jet-flame of pilot-burner ignition is designedin this paper. The research in the multi-tube PDE showed that the jet-flame could ignite the fuel in thePDE chamber. However, there was no detonation wave in the detonation chamber. The result showsthat the stability of pilot-burner needs to be increased. The result shows that, for different inlet pressures, there are different lean limit and oil-rich limits; in the same inlet angle, the lowesttemperature for the occurrence of thermal ignition increased with the increasingly high air pressure. Inthe same air pressure, the lowest temperature for the occurrence of thermal ignition declined with theincreasingly large inlet angle. All of the thermal ignition occurring temperature was higher than900°C.