富氧燃气发生器液氧供应系统频率特性分析

为了研究富氧发生器液氧供应系统的动态特性，详细考虑液氧头腔中的流动过程和喷嘴动力学环节，建立了系统的传递矩阵模型。计算了系统在发生器室压扰动下的频率响应特性，并分析液氧头腔体积、喷嘴压降、喷嘴惯性和发动机工况对液氧供应系统动态响应的影响。结果表明，由于液氧头腔的容积较大，液氧喷注导纳主要取决于头腔和喷嘴的动态特性，出口流量幅值在很宽的频率范围内都较高。增大头腔体积，则增大出口流量的幅值，降低头腔中压力响应幅值。适当提高喷注压降或喷注单元的惯性，都能降低液氧喷注导纳的幅值。在低工况下出口流量幅值在300～800Hz之间增大，不利于该频率范围的耦合稳定性。

Frequency characteristic analysis for LOX feed system of oxidizer-rich preburner

In order to investigate the dynamical characteristics of LOX feed system for the oxidizer-rich preburner, the transfer matrix models were established by detailedly considering the flow progress in LOX manifold and the injector dynamic component. The frequency response characteristics of the system under the gas generator pressure disturbance were computed. The influence of LOX manifold volume, injection pressure drop, injection inertia and engine thrust level on dynamic response of the LOX feed system were analyzed. The results indicate that, due to the large volume of LOX manifold, the LOX injection admittance is mainly depended on the dynamic characteristics of manifold and injector, and outlet flow rate has high response amplitude in wide frequency range. If the manifold volume is enlarged, the outlet flow rate amplitude is increased and the pressure response amplitude is reduced. If appropriately improving the injection pressure drop or the injection inertia, the amplitude of LOX injection admittance can be decreased. At the low thrust level, the outlet flow rate amplitude enlarges at 300-800 Hz, which is a disadvantage to the coupled stability within the frequency range.