火箭发动机喷管分离流动仿真分析

采用数值方法研究在分离状态下的最大推力喷管流动状态,讨论了不同湍流模型对分离流动的影响,在此基础上详细分析了喷管流动中出现气流分离模态由自由激波（FSS）到受限激波（RSS）的变化情况。在稳态仿真基础上开展非稳态分析,并综合小波分析、结构有限元方法分析了侧向载荷影响。研究结果表明,喷管内压强脉动为低频脉动,该脉动频率范围与喷管固有频率有交叠,可为后续的喷管气流分离侧向载荷分析及验证试验提供基础。

Simulation analysis on separation flow in rocket engine nozzle

Flow status of the large expand ratio rocket engine nozzle is studied with numerical method. The influence of the different RANS turbulence models on separation flow is discussed. Based on this, the variation of flow separation modal from free shock separation （FSS） to restricted shock separation （RSS） occurred in the nozzle is analyzed in detail. The unsteady-state analysis is carried out on the basis of steady-state simulation. The effect of lateral load is also analyzed in combination with the wavelet analysis and FEM. The research result shows that the pressure intensity pulsation in the nozzle is low-frequency one, whose frequency range has resonance with inherent frequency of the nozzle. The conclusion laid a foundation for the subsequent analysis and verification test of the lateral load of flow separation in the nozzle.