Experimental Investigation On The Performance Of Low-resistance Pulse Detonation Engine

Pulse Detonation Engine (PDE) is one of the most promising propulsion systems in the21st century. Thispropulsion system has many advantages: higher cycle efficiency, simpler structure, better adaptability andso on. Now the critical question of the engineering application about PDE is that: Most of the thrust hasbeen consumed by its resistance. This paper concentrates on low-resistance pneumatic valve and spoilerfor PDE, so as the way to promote the thrust performance. Some research results have been got out:1） A low resistance pneumatic-valve PDE was designed after analyzing the elements of PDE thrust andresistance, Enlarge the throat area of the pneumatic-valve from30%~35%of the PDE tube area to40%~45%could make a42.7%reduction of the resistance coefficient of the pneumatic-valve.2） Orifice plate obstacles can enhance the turbulence intensity in the detonation tube to accelerate theDDT process but in the meanwhile increase the resistance of PDE. To reduce the blockage ratio of theorifice plate obstacle and reduce the resistance, a kind of orifice plate with circular scatter slits wasdesigned. Air or oxygen in different pressures was filled into the slits-orifice plate obstacle to see how itinfluences the detonation process of PDE. Air-kerosene mixture was also used as filling gas in the finalexperiments. Experimental results indicate that it didn’t work when fill low pressure air into the slits-orifice plate obstacle while continuous burning in the tube was induced when high pressure oxygen wasinjected into the slits-orifice plate obstacle due to too rich or lean regions in the tube. Ethylene injectedinto the oxygen-enriched region adjusted this inhomogeneity. High pressure air played a more active rolethan low pressure air. High pressure kerosene-air mixture seemed to be the most meaningful filling source,with this1750m/s flame propagation velocity and1.5MPa pressure at the end of detonation tube was got.3） A series of experiments focused on thrust augmentation with outer resistance removed wasperformed. A kind of thrust-retrieve equipment to turn inlet back flow into thrust was designed andresearched,105.3N average thrust in400ms episode with0.05MPa intake pressure30Hz operatingfrequency was got, while only58.9N average thrust was got without the thrust-retrieve equipment. Theexperiments indicate that thrust-retrieve equipment could turn the resistance into PDE thrust.4） The impulse of the large throat area pneumatic valve PDE was estimated, thus the resistant in theintake process and the net thrust of PDE in different intake pressure can be calculated easily. Primaryresearch on how to evaluate the performance of the PDE is proved to be useful in future PDE design.