| Summary: | 碩士 === 國立海洋大學 === 機械與輪機工程學系 === 91 === The liquid jet atomization has been widely utilized for many industrial applications. In the combustion chamber, atomized drop size, velocity distribution, breakup length have profound influences on the combustion efficiency and emission pollution. Despite a great quantity of past experimental studies, the physical process of atomization phenomenon has not been fully understood. In the present study, the atomization of a coaxial injector in the liquid rocket engine was numerically investigated. Based on the jet surface wave instability analysis on the interface of liquid and gas, the atomization model for the high-speed liquid jets was established and coupled with Jet Embedding Method, which needs only economic adaptive grid system. Accordingly, the liquid jet core and drop formation in the atomization process can be numerically predicted.
The wave instability of liquid propelled fuel jets was first analyzed in the present study. Using the numerical method to solve the dispersion equation, growth rates of instable waves for all spectrum can be predicted along the liquid jet surface. Then, the basic equations governing the flow field, determining the formation of the liquid jet core and the variations of the liquid jet surface, were set up by the Jet Embedding method. Thus, coupled with the analysis of wave instability, the atomization model for drop formation can be established to predicted the flow structure, drop breakup rate, and drop size distribution. Finally, the past test data for a coaxial injector of the Space Shuttle Main Engine have been used to verify the present numerical model.
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