考虑径向加质的固体火箭发动机内流场整体稳定性分析

Biglobal stability analysis for the side-induced flow in solid rocket motors

基于整体流动稳定性方法,分析了大长径比固体火箭发动机内径向加质流的稳定性特性,采用零应力出流边界条件,利用谱配置方法数值求解扰动方程得到了特征谱和对应的特征函数。发现长径比增加到10时,特征值开始从时间稳定变为不稳定。特征函数显示速度扰动幅值沿轴向逐渐增大,且向内部扩张,与实验中观察到的现象一致,理论计算结果准确地吻合了冷流实验中出现的速度波动频率。研究工作为分段固体火箭发动机的稳定性分析提供一种快速、有效的方法。

A general linear stability approach was applied to investigate the aerodynamic stability of the side-induced flow in solid rocket motors with large length to radius ratio. The eigenvalue problems were discretized by a spectral collocation method and then solved numerically using MatLab software. The discrete eigenvalue set and corresponding eigenfunctions were obtained. Results reveal that when length to radius ratio （L/R） is larger than 10, some eigenmedes become temporal instable. The amplitudes of dis- turbance velocities increase with the axial locations and instable areas spreading toward the center line, which are consistent with experimental observations. Comparisons between theoretical results and experimental data also show well agreement in the frequen- cies of disturbance velocities.