Multi-element injectors have been used in liquid rocket engines to obtain high thrust, and the gas-centered swirl coaxial injector is a representative injection system because it provides high mixing performance. Investigations of the spray characteristics of injection systems have focused on the characteristics of single-element injectors, including the spray angle, breakup, and atomization mechanism of the liquid sheet formation. However, the spray characteristics of multi-element injectors need to be studied because of their usage in real rocket engine systems. In this paper, spray patterns and interacting spray under different injection conditions are analyzed using the backlight imaging technique, and the dominant flow fields are observed using the dynamic mode decomposition method. The spray angle in the case of the gaseous nitrogen with a high Reynolds number is calculated to be lower than the case with a low Reynolds number. From the averaged images, it is found that there are two dominant flow fields: one is located in the vicinity of the injector head and the other is in the interacting spray zone, which is related to a secondary breakup via an adjacent injector. As a result of the dynamic mode decomposition analysis, however, the spray zone near the injector is confirmed to be a more dominant flow field than the interacting spray zone.

中文翻译：

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不同喷射条件下相互作用喷雾的多元旋流同轴喷射器的喷射模式

多元件喷射器已被用于液体火箭发动机以获得高推力，而气心旋流同轴喷射器是一种具有代表性的喷射系统，因为它提供了高混合性能。对喷射系统喷雾特性的研究主要集中在单体喷射器的特性上，包括喷雾角度、破裂和液片形成的雾化机制。然而，由于多元件喷射器在实际火箭发动机系统中的使用，需要对其喷雾特性进行研究。在本文中，使用背光成像技术分析了不同喷射条件下的喷雾模式和相互作用喷雾，并使用动态模式分解方法观察了主导流场。在具有高雷诺数的气态氮的情况下计算喷射角小于具有低雷诺数的情况。从平均图像中，发现有两个主要流场：一个位于喷射头附近，另一个位于相互作用的喷雾区，这与通过相邻喷射器的二次破碎有关。然而，作为动态模式分解分析的结果，喷射器附近的喷雾区被证实是比相互作用的喷雾区更占主导地位的流场。这与通过相邻喷射器的二次破裂有关。然而，作为动态模式分解分析的结果，喷射器附近的喷雾区被证实是比相互作用的喷雾区更占主导地位的流场。这与通过相邻喷射器的二次破裂有关。然而，作为动态模式分解分析的结果，喷射器附近的喷雾区被证实是比相互作用的喷雾区更占主导地位的流场。