同轴离心式喷嘴燃烧稳定性增长率识别  

Determination of the growth rate of combustion instability of swirl coaxial injectors

作　　者：杨尚荣 吴林龙 于涵 杨宝娥 YANG Shangrong;WU Linlong;YU Han;YANG Baoe(Science and Technology on Liquid Rocket Engine Laboratory,Xi’an Aerospace Propulsion Institute,Xi’an 710100,China)

机构地区：[1]西安航天动力研究所液体火箭发动机技术重点实验室,西安710100

出　　处：《振动与冲击》2023年第18期332-337,共6页Journal of Vibration and Shock

基　　金：国家自然科学基金(51606138)。

摘　　要：为确定同轴离心式喷嘴燃烧不稳定的线性增长率,基于随机动力学Fokker-Planck体系系统识别方法,利用脉动压力时间序列识别喷嘴4种工况下的增长率,并分析了结果的不确定性和参数敏感性。结果表明:变换脉动压力的单位进行识别,增长率不变,饱和系数和噪声强度存在确定的变换关系,且三者的识别精度不变;负增长率的声模态在噪声作用下也可能发生较大幅值的压力振荡;增加脉动压力采样时间可以提高增长率的识别精度,不同工况下存在各自较优的采样率。从脉动压力时间序列线性增长阶段识别增长率同样需要考虑噪声导致的不确定性。In order to determine the linear growth rate of combustion instability of swirl coaxial injectors,the output-only system identification method,based on the Fokker-Planck formalism in stochastic dynamics,was used to identify the growth rate based on the dynamic pressure time series under four operating conditions.Uncertainty and sensitivity analysis were also conducted.It is shown that the growth rate is unchanged after conversion of pressure units.There is a determinate conversion relationship between the saturation coefficient and noise intensity.And the accuracy of identification for the three parameters is consistent.Large amplitude pressure oscillations may occur for acoustic modes with negative growth rates due to the influence of noise.The improved accuracy of identification can be realized by increasing the sampling time,and corresponding to each operation condition,there is an appropriate optimal sampling rates.It is also found that uncertainties introduced by combustion noise need to be considered when growth rates are identified from the linear growth region of dynamic pressure time series.

关 键 词：同轴离心式喷嘴 燃烧不稳定 燃烧噪声 增长率 输出识别 

分 类 号：V231.1[航空宇航科学与技术—航空宇航推进理论与工程]