| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 106 === The combination of W2(kerosene-base fuel) and hydrogen peroxide is a promising bipropellant system due to its low cost, low toxicity, high propulsive performance, and most importantly hypergolic characteristics. Liquid cyclonic injector is a premixed type bipropellant injector that it is characterized by simple configuration and capability to accrue heat to generate the require auto-ignition in the internal open space. In the injector, liquid fuel and oxidizer are tangentially injected into a small cylindrical chamber to mix. In this research, the relation of injector geometry design and hypergolic phenomena is discussed.
The results show that ignition delay time is reduced either by lengthening the cylindrical chamber or changing the fuel injection angle horizontally and vertically, that enhances the gas phase reaction rate and liquid phase catalytic reaction rate, respectively. Also, using the design of tapering off cylindrical chamber could make plum more concentrated. In each hot-fire experiment, manganese dioxide type of powder-like coverage is found on the inner surface of the cylinder and is removed. Using the design of changing the fuel injector upward by 15 degrees, without removing manganese dioxide coverage shows an averaged ignition delay time of 0.51 seconds and a standard deviation of 0.26 second, which are 79% and 66% shorter and smaller than that of the cleaned ones. This indicates that the manganese dioxide coverage on the wall possesses strong catalytic effect to start the auto-ignition reactions and is an important information for future injector improvement.
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