管型装药固体发动机燃烧室振动与内弹道研究

【作者】 孟伟；

【导师】 鲍福廷；

【作者基本信息】 西北工业大学 ， 航空宇航推进理论与工程， 2007， 硕士

【摘要】 固体火箭发动机在工作过程中经常会出现振动及过载情形。这些结构振动及过载会对固体火箭发动机内流场和装药燃烧产生很大的影响。本文主要通过数值仿真，研究管型装药固体火箭发动机燃烧室结构振动对内弹道的影响。 固体火箭发动机燃烧室结构振动的引入，使推进剂燃烧和燃气流动产生了改变，导致整个内流场发生很大的变化。传统的固体火箭发动机内弹道方程已不适应结构振动下流场的计算。为此，本文深入研究了结构振动对内弹道的影响，参考传统一维非定常内弹道方程的推导过程，建立了考虑燃烧室结构振动的一维非定常内弹道方程。另外，结构振动加速度对推进剂燃速的影响十分显著，本文还详细介绍了一种加速度敏感性的燃速模型。 本文在建立发动机燃烧室结构振动模型的过程中，充分利用了管型装药发动机燃烧室结构和载荷的轴对称性。在给定的燃烧室截面内，对于流场压强变化引起的结构径向振动，根据振动理论和弹性力学得到了简化的等效径向振动方程。对于燃烧室非刚性的轴向振动，将其合理的简化为有阻尼的弹性杆件的纵向振动问题。 本文考虑了结构阻尼、推进剂燃烧等因素来增强数值模型对结构振动影响的预测能力。使用数值方法对发动机燃烧室结构振动模型和内弹道模型进行了耦合计算。数值模型预测了不同工作状态下的燃烧室结构径向、轴向振动引起的有限振幅的压力波动。研究表明：结构振动和推进剂燃烧、燃气流动的相互影响，导致固体发动机的结构振动加剧了内弹道的不稳定性。更多还原

【Abstract】 Solid rocket motors are subjected on occasion to strong oscillatory axial and radial acceleration environments. The structure vibration can play an important role in influencing the inner flows field and the burning rate of the propellant. The coupling of structural vibration with the internal ballistic of a cylindrical-grain solid rocket motor is investigated through numerical simulation.The structural vibration of solid rocket motors causes great changes of the inner flows field, thus burning rate of the propellant and flow condition of gas changes greatly, and the traditional internal ballistic equations become inapplicable. Therefore, with considering the effect due to structural vibration, one-dimensional nonsteady internal ballistic equations are built through investigate the influence of the structural vibration and refer to the traditional one-dimensional nonsteady internal ballistic equations, In addition, a burning rate model with considering the acceleration effects is introduced because vibration acceleration influences the burning rate obviously.The structure and load of a cylindrical-grain solid rocket motor chamber is symmetrical, which is sufficient used during the process of building the structural vibration model of solid rocket motor. According to elasticity theory and vibration mechanics, a simplified ordinary differential equation applies for structural radial vibration due to flow pressure. The nonrigid axial vibration model of the chamber can be simplified as a longitudinal vibration model of the damping elastic beam.The interaction of structural vibration and the internal ballistics of solid rocket motor is analyzed and the influence of vibration of the structure on the internal ballistics are found. The numerical model predicts that both axial and radial vibration can result in a limited pressure wave strength. The relationship among structural vibration mechanism, burning mechanism and gas dynamic mechanism is compactness. It is conceded that structural vibrations of solid rocket motor can strength the nonsteady internal ballistic behavior.更多还原