Please use this identifier to cite or link to this item: `http://hdl.handle.net/11455/2245`
 標題: 氣壓水箭推進性能之增進分析Analysis of Propulsion Performance Enhancement for Air-Pressurized Waterjet Rocket 作者: 吳信漢Wu, Shin-Han 關鍵字: 氣壓水箭;air-pressurized waterjet rocket;推進性能;質能分離;拉氏雷諾輸送公式;動量方程式;總動力功率;推力功率;輪迴運算;propulsion performance;separated energy and mass;Lagrangian Reynolds'' transport equation;momentum equation;total kinetic power;thrust power;convolution 出版社: 機械工程學系 摘要: 氣壓水箭是以高壓氣體當動力來源，以水當推進劑，常能以較少能量獲得良好的推進性能。與傳統火箭比較，其特點有：構造簡單、質能分離、安全環保、成本低廉等。近幾年從媒體資訊可知氣壓水箭在型態設計上之多樣性，然而在基本理論方面，一直缺乏正確的總動力功率之觀念及公式以進行深入分析，直到中興大學機研所李興軍提出革命性之經典論文才得以突破。傳統上，西方國家一直以零初速觀念來發射火箭，如同向後開槍，因此其推進效率不高，並耗費相當多的額外成本。一般改善飛行性能之方法是增加推進劑以換取飛行高度，本文卻以增加火箭整體未點火前初速之創新觀念來增進推進效率，其基本的原理乃是奠基於減少噴出流之能損。本文將融合李興軍所提出之拉氏雷諾輸送公式、動量方程式、火箭之總動力功率及推力功率等突破性觀念，對氣壓水箭之飛行狀態做一個較完整、清楚、自然，且有系統的分析。並利用此一增初速之先進觀念，以數值模擬來證明增初速對水箭飛行效率之增進效益。在處理過程中，先聯立通化動量方程式及總動力功率公式，再運用數值積分方法、輪迴運算與等熵過程之觀念，將複雜的內流場問題徹底解決。數值模擬所得結果明確證明本文增初速之創新觀念對於氣壓水箭推進性能之增進，有極重大之影響，其效率可輕易獲得數百個百分點之驚人改進，並奠定了此一先進的增效觀念推廣於大型人造衛星運載火箭之堅實基礎。The air-pressurized waterjet rocket uses compressed air as the power source and water as the propellant; it often can achieve a better propulsion performance with less energy. Comparatively, it is characterized with simplicity, separated energy and mass, safety, environmentally friendliness, and minimal cost. Recently, news media show that there are various models of air-pressurized waterjet rockets, however, there still lacks the correct concept and total kinetic power equation for advanced analyses in associated basic theories. This problem remained unsolved until a revolutionary propulsion paper was presented by H. J. Lee of National Chung-Hsing University. Traditionally, pioneering countries always launch rockets with the concept of zero initial velocity, which is like shooting backward with fairly low energy efficiency for the rifle, and thus wasting extra cost. Generally, designers tend to increase propellant in order to improve the propulsion performance and attain higher altitude. Alternately, in this paper we use the novel concept of increasing the initial velocity of the rocket before igniting for improving efficiency. The basic theory is reducing the energy loss of the outgoing fluid. This article will synthesize the new concepts of Lagrangian Reynolds'' transport equation, momentum equation, total kinetic power, and thrust power to get a more complete, clear, natural, and systematic analyses of the flying state of air-pressurized waterjet Rocket. Further, we prove the propulsive efficiency enhancing effect of novel concept of increasing initial velocity with numerical simulation. In the solving process, we combine generalized momentum equation and generalized total kinetic power equation first, and then use the concepts of the numerical integration, convolution, and isentropic process to solve the complicated internal flow field completely. The results of numerical simulation clearly and definitely prove that the concept of increasing the initial velocity does have great effect on propulsion performance of air-pressurized waterjet rocket. The improvement may easily reach an amazing several hundred percents. This original study thus has laid a solid foundation for further promoting the original concept of increasing initial velocity to large satellite-launching rockets. URI: http://hdl.handle.net/11455/2245 Appears in Collections: 機械工程學系所