【作者】 钟涛；

【导师】 张为华；

【作者基本信息】 国防科学技术大学 ， 航空宇航科学与技术， 2005， 博士

【摘要】 本文采用理论分析和数值仿真方法对大长径比固体火箭发动机点火瞬态过程进行了系统研究。 理论分析着重研究了点火燃气与推进剂表面传热及推进剂内瞬态热传导规律。针对侧壁多孔管式点火装置,基于相似性分析,采用门格勒变换方法将点火燃气与药柱内孔表面传热问题转化为射流撞击平面传热问题,由此推导得到点火燃气射流与推进剂表面间传热系数表达式。理论分析表明,抛物型经典傅立叶热传导定律无法准确描述瞬态传热过程。通过分析研究点火瞬态过程中推进剂内部急速热传导存在的非傅立叶效应,推导得到具有双曲性质的固体推进剂瞬态热传导方程。设计试验测量得到推进剂热松弛时间,经与热作用时间比较验证了固体推进剂瞬态传热过程中的非傅立叶效应。 在点火装置自由喷射点火试验观测基础上,考虑大长径比固体火箭发动机点火装置存在的发火延迟与药块点燃过程,对点火质量流率预示模型进行修正,效果良好。集点火装置、燃烧室和喷管于一体,建立了大长径比固体火箭发动机点火瞬态过程一维、二维和三维非定常流动仿真模型,数值计算结果与试验结果具有良好一致性,间接验证了仿真模型与计算软件的正确性。根据一维仿真结果建立了推进剂表面火焰传播过程与燃烧室升压速率的对应关系;根据二维仿真结果讨论了提高点火药量利用率的途径;根据三维仿真结果对点火瞬态过程中尾部翼槽内火焰传播过程进行了深入分析。研究表明,火焰传播结束时刻对应于燃烧室升压速率极大值,尾部翼槽内火焰传播过程不连续。 从微分形式非线性粘弹性本构方程出发,分析了推进剂对点火过程瞬态载荷的响应特性,对非均匀载荷下药柱结构完整性进行了初步分析。 采用蒙特卡罗方法分析了点火装置性能散布及其影响因素;引入均匀设计方法分析了大长径比固体火箭发动机点火瞬态过程性能散布规律,由此提出降低点火瞬态过程性能散布的途径。 本文研究成果为解决大长径比固体火箭发动机点火装置设计、点火特性分析及点火过程性能散布控制等众多工程实际问题提供理论依据与分析工具,具有重要理论意义和工程应用价值。更多还原

【Abstract】 This dissertation integrates theoretical analysis and numerical simulation method to investigate the ignition transient process of large aspect ratio solid rocket motors.Theoretical analysis emphasizes on heat transfer both inside propellant and between igniter exhaust and internal grain surface. For igniter device with side holes, by adopting Manglar Transform and with achievements in heat transfer study on jet impinging on plane, formula of heat transfer coefficient for igniter exhaust impinging on internal grain surface is obtained.Mathematic analysis demonstrates that classic Fourier heat transfer formula can not properly describe such wave propagation phenomena as transient heat transfer inside propellant. After affirming the existence of non-Fourier effect, the hyperbolic equation suited for describing rapidity heat transfer process inside propellant is obtained. Experiment is designed to measure heat relaxation time. Comparison with heat action time validates above analysis.To found basis of numerical simulation, the igniter mass flow rate predication model is first modified to consider such effect as ignition delay and burning process occurred in igniter device for large aspect ratio solid rocket motors.The mathematical models suited for 1-D,2-D and 3-D unsteady flow simulation during ignite transient process of large aspect ratio solid rocket motors are constructed repectively. Corresponding software is accomplished. Comparison between simulation and experiment result verify the correctness of both mathematical model and simulation program.1-D simulation results are adopted to construct the relationship between pressure rise rate and flame spreading process along propellant surface; Appropriate step to enhance efficiency of ignition charge is discussed based on 2-D simulation results and flame spreading process in fin slots is analyzed with 3-D simulation results. The study indicates that the end of flame spread over grain surface corresponds to max value of pressure rise rate and the flame is not continuous in fin slots.Response characteristic of solid propellant to sudden load is studied based on differential nonlinear viscoelasticity constructural equation during ignition transient process. Structure integrity of propellant is also analyzed.Monte Carlo method is adopted to study performance dispersion of igniter device. After introducing Uniformity Design Method, the performance dispersion during ignition transient process is investigated. Measures to depress dispersion band are also discussed.The research work of this dissertation not only brings forward new viewpoint for theoretic study such as heat transfer analysis, but also provides foundation for solving such engineering problem as ignite device design, ignite performance dispersion control and ignite characteristic analysis. The achievements will have significant effect on both theoretic study and engineering practice.更多还原