【作者】 钟战；

【导师】 王振国；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2008， 硕士

【摘要】 本文通过理论分析、试验研究和数值模拟等方法研究了燃气发生器的点火特性与燃烧性能,发现了影响直接燃烧式三组元燃气发生器点火特性与燃烧性能的关键因素及其影响规律,提出了改善燃气发生器点火特性与提高燃气发生器燃烧性能的方法,并得到了试验验证。研究结果加深了对燃气发生器内部工作过程的理解,对燃气发生器的应用和优化设计有重要指导意义。通过理论分析指出了燃气发生器研究的重点与难点,确定了燃气发生器研究的主要内容。分析表明:水的加入在降低燃烧室温度的同时,也显著降低了燃气发生器的点火与燃烧性能;氧气/Lf80燃气发生器燃烧效率与液滴蒸发速率密切相关;气体流速大导致火焰难以在燃烧室内稳定,是空气/ Lf80-01燃气发生器点火困难的主要原因。采用理论分析与试验研究方法,研究了影响燃气发生器点火性能的主要因素及其影响规律。研究结果表明:点火温度对火炬点火器的点火能力有重要影响;燃气发生器点火困难的根本原因在于水的加入使化学反应与火焰传播速率大幅下降、从而导致火焰不容易稳定;点火热气流温度、燃料含水量、燃烧室内气体流速、余氧系数、总流量等因素对燃气发生器点火性能影响很大。在此研究基础上,提出了合适的点火方案,可以保证燃气发生器具有非常高的点火可靠性。通过试验研究和数值模拟方法研究了氧气/Lf 80燃气发生器的燃烧性能。通过试验研究了喷嘴结构、燃料含水量、扰流环、余氧系数和总流量等因素对燃气发生器燃烧性能的影响,结合数值计算结果分析了燃气发生器燃烧过程的特点,以及扰流环对燃气发生器燃烧过程的影响。研究结果表明:水的加入对燃烧室的降温作用明显,整个燃烧室内温度较低;液滴蒸发速率是影响燃气发生器燃烧效率的关键因素,提高燃气发生器燃烧效率的主要方法是改善液滴的蒸发。通过改进喷嘴结构、降低燃料含水量、在燃烧室内安装扰流环等措施均显著提高了燃烧效率,其中在燃烧室内安装扰流环还可以提高燃气发生器的燃烧稳定性。更多还原

【Abstract】 The ignition characteristic and combustion performances of the gas generator are studied by means of theoretical analysis, experimental investigation and numerical simulation in the paper. The factors that have significant influences on the ignition process and combustion performances of the gas generator and the influence laws are respectively acquired. Several measurements that could improve the ignition characteristic and combustion performances of the gas generator are presented and verified by tests. The results are helpful to understand the inner operation process of the gas generator and important for application and optimization design of the gas generator.Key difficulties in the research of the gas generator are pointed out through theoretical analysis, so the main research contents are confirmed. The analysis shows that the ignition and combustion performances of the gas generator are markedly worsened although the combustion chamber temperature is lowered by adding water ; Combustion efficiency of the gas generator with Oxygen/ Lf80 is closely related to the evaporation rate of the liquid fuel of Lf80;The gas flow velocity being too high so the flame could not stay steadily in the combustion chamber is the main reason of the ignition difficulty in gas generator with Air/ Lf80-01 propellants.Based on the theoretical analysis and experimental results, the primary factors affecting markedly the ignition characteristic of the gas generator as well as the influence laws are studied. The results indicate that the combustion gas temperature plays the most important role on the ignition capability of the torch igniter. For gas generator, the ignition difficulty mainly comes from the addition of water that slows down the chemical reaction rate and flame propagation speed. The results also indicate that many factors have obvious influence on the ignition characteristic of the gas generator, including the temperature of the igniting combustion gas of torch igniter, the water fraction of the special fuel, the gas flow velocity in the combustion chamber, excess oxidizer coefficient and mass flux of propellants. On the foundation of the research, the paper presents a right method outstandingly improving the ignition reliability of the gas generator.The combustion performance of the gas generator with Oxygen/ Lf80 propellants is studied by experiments and numerical simulation. The influence on the combustion performance of the gas generator of injector structures, water fraction of liquid fuel, disturbing ring, excess oxidizer coefficient and mass flux are studied by experiments.According to the numerical simulation, the combustion characteristics of the gas generator with disturbing ring are analyzed. The results show that addition of water has a notable effect on lowering the combustion temperature since the whole combustion chamber has a low temperature. The evaporation rate is the essential factor, which has great influence on the combustion efficiency of the gas generator, so the efficient method to increase the combustion efficiency is to speed up the evaporation. The combustion efficiency can also be notably improved by optimizing the injector structure, decrease the water fraction of fuel and fixing the disturbing ring in the combustion chamber through which the combustion stability is also improved.更多还原