Incoming standards on NO x emissions are motivating many aero-engine manufacturers to adopt the lean burn combustion concept. One of the most critical issues affecting this kind of technology is the occurrence of thermo-acoustic instabilities that may compromise combustor life and integrity. Therefore the prediction of the thermo-acoustic behaviour of the system becomes of primary importance. In this paper, the complex interaction between the system acoustics and a turbulent spray flame for aero-engine applications is numerically studied. The dynamic flame response is computed exploiting reactive URANS simulations and system identification techniques. Great attention has been devoted to the impact of liquid fuel evolution and droplet dynamics. For this purpose, the GE Avio PERM (partially evaporating and rapid mixing) lean injection system has been analysed, focussing attention on the effect of several modelling parameters on the combustion and on the predicted flame response. A frequency analysis has also been set up and exploited to obtain even more insight on the dynamic flame response of the spray flame. The application is one of the few in the literature where the dynamic flame response of spray flames is numerically investigated, providing a description in terms of flame transfer function and detailed information on the physical phenomena.

中文翻译：

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航空发动机喷雾火焰动态火焰响应的数值分析

新的NOx排放标准正在激励许多航空发动机制造商采用稀薄燃烧的概念。影响此类技术的最关键问题之一是热声不稳定性的发生，可能会损害燃烧器的寿命和完整性。因此，预测系统的热声特性变得至关重要。在本文中，数值研究了航空发动机应用中的系统声学和湍流喷射火焰之间的复杂相互作用。动态火焰响应是利用反应性URANS模拟和系统识别技术来计算的。液体燃料的发展和液滴动力学的影响已经引起了极大的关注。以此目的，分析了GE Avio PERM（部分蒸发和快速混合）稀薄喷射系统，将注意力集中在几个建模参数对燃烧的影响以及预计的火焰响应上。还进行了频率分析，并利用它来获得对喷雾火焰的动态火焰响应的更多了解。该应用程序是文献中为数不多的对喷雾火焰的动态火焰响应进行数值研究的应用程序之一，提供了关于火焰传递函数的描述以及有关物理现象的详细信息。还进行了频率分析，并利用它来获得对喷雾火焰的动态火焰响应的更多了解。该应用程序是文献中为数不多的对喷雾火焰的动态火焰响应进行数值研究的应用程序之一，提供了关于火焰传递函数的描述以及有关物理现象的详细信息。还进行了频率分析，并利用它来获得对喷雾火焰的动态火焰响应的更多了解。该应用程序是文献中为数不多的对喷雾火焰的动态火焰响应进行数值研究的应用程序之一，提供了关于火焰传递函数的描述以及有关物理现象的详细信息。