Abstract: In order to obtain the variation law of the damping characteristics of the rocket motor with complicated grain during the working process， the numerical simulation of the combustion chamber structure at different working moments was carried out by using the finite element analysis method， and the acoustic modes and their variation law in the working process of the complex charge engine were obtained. Based on this， the common damping factors in the combustion process of the complex charge engine was calculated and analyzed. The results show that the percentage of nozzle damping coefficient and wall damping coefficient to total damping coefficient decreases gradually， while the percentage of particle damping coefficient to total damping coefficient increases gradually. At the later stage of engine operation， the damping coefficient of engine is the smallest， which results in poor stability and small disturbance is easy to be enlarged. Among all dampers of the engine， nozzle dampers play a dominant role in the early stage of engine operation， while particle dampers play a dominant role in the later stage of engine operation.

Key words: Solid rocket motor;Complicated grain;Acoustic mode;Damping characteristics;FEM

摘要： 为了获得复杂装药发动机工作过程中阻尼特性的变化规律，首先利用有限元分析方法对不同工作时刻的燃烧室声腔结构进行了数值仿真计算，得到复杂装药发动机工作过程中的声模态及其变化规律，基于此，计算并分析了复杂装药发动机燃烧过程中常见阻尼因素的变化规律。结果表明，喷管阻尼系数与壁面阻尼系数占总阻尼系数百分比逐渐减小，相反微粒阻尼系数占总阻尼系数的百分比逐渐增大，在发动机工作后，发动机阻尼系数最小，从而导致发动机后期的工作稳定性较差，小扰动易被扩大为大扰动； 在发动机的所有阻尼中，喷管阻尼在发动机工作初期起主导作用，而微粒阻尼在工作后期起主导作用。

关键词: 固体火箭发动机;复杂装药;声模态;阻尼特性;有限元分析