fundamental study on pulse detonation engine with liquid fuel for aerospace propulsion system

Paper number

IAC-08.C4.5.14

Author

Mr. Ryuji Nakawatase, Kyushu University, Japan

Coauthor

Mr. Yoichiro Nishimura, Kyushu University, Japan

Coauthor

Prof. Shigeru Aso, Kyushu University, Japan

Coauthor

Dr. Yasuhiro Tani, Kyushu University, Japan

Year

2008

Abstract

Pulse Detonation Engines (PDEs) have the potential to revolutionize aerospace propulsion system for future aerospace vehicles. One reason for this seems to be the promise of high efficiency due to the fact that PDE cycles operate with near-constant volume combustion. Furthermore, it is often argued that PDEs have fewer parts and are much less mechanically complex than other aerospace propulsion systems. In turn, this makes them considerably less expensive.

The PDE will require the use of a liquid fuel for many practical applications because liquid fuel is denser compared with gaseous fuel. It is widely recognized that detonations propagating at about the equivalent gas-phase Chapman-Jouguet detonation velocity can be attained in a variety of fuel-oxygen system if the droplets of liquid fuels are fine enough. The propagation velocity of liquid fuel with large droplets is significantly lower than that of gas-phase. Therefore it is important to generate fine droplets. Generally liquid fuel is atomized by fuel injection nozzle. The method is usually used for diesel engines of automobile and the diameters of the droplets are relatively large and of the order of several ten micrometers. In the present study the ultrasonic atomizer is applied in order to generate finer droplets for the first time.

To evaluate the application to PDEs of the ultrasonic atomizer a new PDE facility has been built in the present work. Jet A-1 is used as a liquid fuel and oxygen as an oxidant. Jet A-1 is widely used as a fuel for the commercial airplanes. The dimensions of the detonation tube are 50 mm diameter by 2348 mm long. The hydrogen/oxygen pre-detonator is used to ignite. The pre-detonator is installed at the end of the detonation tube. To detect combustion waves, two-needle ion probes are mounted along the tube wall with 200 mm intervals. Experiments are performed with Jet A-1 and oxygen mixtures initially at atmospheric pressure. Through the present experiments the present authors have succeeded in the initiation of detonation in atomized Jet A-1 droplets which are generated by ultrasonic atomizers. The successive experiments are in progress in order to increase the propagation velocity of detonation for the application of aerospace propulsion system.

The detailed results from these experiments will be presented at the symposium.

Abstract document

IAC-08.C4.5.14.pdf

Manuscript document

IAC-08.C4.5.14.pdf (🔒 authorized access only).

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