The acoustic coupling between the injection system and the acoustic fluctuations in liquid rocket engine combustion chambers is an important issue in the understanding of the thermo-acoustic instability phenomenon. This paper presents the results of a wide-ranging parametric investigation of the acoustic response of a two-phase injection system submitted to a forced high-amplitude transverse acoustic field. Two domes, one for the gas and one for the liquid, were expressly designed to feed three identical coaxial injectors. The internal mode shapes of the domes were characterized by measuring pressure signals at different locations in the domes. Experimental mode shapes showed good agreement with those predicted by numerical simulations. Acoustic pressure amplitudes up to 23% of those induced in the main cavity can be found in both the gas and liquid domes. The response efficiency in a dome depends on the position of the injectors’ exit in the acoustic field.

中文翻译：

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注入系统对高频横向声场的声学响应

喷射系统与液体火箭发动机燃烧室中的声学波动之间的声学​​耦合是理解热声不稳定性现象的重要问题。本文介绍了对两相注入系统在强制高振幅横向声场作用下的声学响应进行的广泛参数研究的结果。专门设计了两个圆顶，一个用于气体，一个用于液体，以供送给三个相同的同轴注射器。圆顶的内部模式形状通过测量圆顶中不同位置的压力信号来表征。实验模式形状与数值模拟预测的形状具有很好的一致性。在气体和液体圆顶中都可以发现高达23％的主腔声压振幅。圆顶中的响应效率取决于喷射器出口在声场中的位置。