Based on the URANS equation, a numerical simulation is carried out for acoustic properties of the thruster chamber with coaxial injectors and plenum chamber in a liquid rocket engine. Pressure oscillations with multiacoustic modes are successfully excited in the chamber by using the constant volume bomb method. FFT analysis is applied to obtain the acoustic properties of eigenfrequencies, power amplitudes, and damping rates for each excited acoustic mode. Compared with the acoustic properties in the model chamber with and without an injector as well as with and without the plenum chamber, it can be found that the injector with one open end and one half-open end still can work as a quarter-wave resonator. The power amplitudes of the acoustic mode can be suppressed significantly when its eigenfrequency is close to the tuning frequency of the injector, which is achieved by Cutting down the pressure Peak and Raising up the pressure Trough (CPRT). Compared with the acoustic properties in the model chamber with and without the plenum chamber, it can be found that 1L acoustic pressure oscillation is inhibited completely by the plenum chamber and other acoustic pressure oscillations are also suppressed in a different extent. The injector and plenum chamber have a little effect on the eigenfrequencies and damping rate of each acoustic mode. For multimode pressure oscillation, it is better for tuning frequency of the injector closing to the lower eigenfrequency acoustic mode, which will be effective for suppression of these multiacoustic modes simultaneously.

中文翻译：

---

同轴注入器和全压腔推进器腔室的声学特性研究

基于URANS方程，对液体火箭发动机中带有同轴喷油器和增压室的推进器室的声学特性进行了数值模拟。通过使用恒定体积炸弹方法，可以在腔室内成功激发具有多声模式的压力振荡。应用FFT分析以获得每种激发的声学模式的本征频率，功率幅度和阻尼率的声学特性。与带有和不带有注入器以及带有或不带有充气室的模型腔中的声学特性相比，可以发现带有一个开口端和一个半开口端的注入器仍然可以充当四分之一波长谐振器。当其固有频率接近喷油器的调谐频率时，可以通过降低压力峰值和升高压力槽（CPRT）来显着抑制声学模式的功率幅度。与具有和不具有增压室的模型室中的声学特性相比，可以发现，增压室完全抑制了1L的声压振荡，并且在不同程度上也抑制了其他声压振荡。进样器和增压室对每种声学模式的本征频率和阻尼率影响很小。对于多模压力振荡，最好将喷油器的频率调整到接近较低的本征声模式，