| Summary: | 碩士 === 國立中興大學 === 機械工程學系 === 91 === Abstract
In comparison with conventional rockets, the air-pressurized waterjet rocket is characterized with simplicity, low cost, science, interest, nature, green, safety, exercise and education. Despite of its popularity for years, there is no associated basic theories for air-pressurized waterjet rocket. This problem remained unsolved until a series of revolutionary papers with novel theorems of Lagrangian Reynolds transport equation, momentum equation, total kinetic power and thrust power were presented recently by H. J. Lee of National Chung-Hsing University. In the propulsion analysis process, except for considering the thrust of waterjet rocket, the dynamics analysis of cable is also quite important. Therefore, this research is divided into two parts, first we synthesize above theorems to analyze propulsion dynamics of waterjet rocket without towing cable. Secondly, we apply towing cable dynamics theorem to analyze its motion, and use fouth- and fifth-order Runge-Kutta formulations to find cable towing force. Furthermore, we combine above formulas to solve the simultaneous partial differential equations, via numerical simulation to treat the propulsion dynamics problem of waterjet rocket with towing cable. Conventionally, the rope-pulling process is always assumed a no-energy-loss process, this paper will explain the erroneous concept. The crux of the matter is that we should recognize the process of towing cable as a perfectly inelastic impact, for which there must be an amount of energy being transformed. According to this reasoning, we have promoted the analysis precision substantially, and prove the mutual correctness of theorems and experiments. Literature shows, propulsion dynamics analysis of air-pressurized waterjet rocket with towing cable has not been attempted before. Thus, in regard of air-pressurized waterjet rocket with towing cable, this pioneering research leads to intergrate the advanced theorems of propulsion dynamics analysis, numerical simulation, and real-life experiments to provide important basis for associated research in the future.
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