翼柱型与环向开槽型燃烧室声学特性对比

Comparative study on acoustic characteristics between finocyl and ring groove grain combustion chambers

为了解决大长径比固体火箭发动机研制中出现的声不稳定问题,本文对典型翼柱装药和环向开槽装药发动机燃烧室进行了声模态和声学响应分析。通过时-频联合分析的方法,得出了2种结构燃烧室随燃面退移的声频变化规律和关键位置的声学响应特性变化规律。研究表明:翼柱型和环向开槽型发动机的前2阶声频随工作时间先减小再增大;燃烧室内的特征结构对声频有明显影响;在发动机头部,环向开槽型发动机的1阶声振幅是翼柱型发动机的34.5%。在声基频下,环向开槽型发动机声学稳定性较翼柱型发动机更高。

To solve the acoustic instability problem in the development of solid rocket motors with large aspect ratios,the acoustic mode and response analysis of two typical combustion chambers(finocyl and ring groove grain combustion chambers)is performed in this study using the finite element method.The acoustic frequency variation law in the burning surface retreat and the change law of acoustic response characteristics in the critical positions of the two structures are obtained using the joint time-frequency analysis method.The results show that the first two-order acoustic frequencies of the finocyl and ring groove grain motors initially reduce and then increase with operating time,and the feature structure in the combustion chamber has an evident influence on the acoustic frequency.In addition,at the head end of motors,the first-order acoustic amplitude of the ring groove grain motor is 34.5%of that of the finocyl one.At the fundamental acoustic frequency,the ring groove grain has higher acoustic stability compared with the finocyl grain motor.