From a system perspective, the entropy generation of an aeroengine is directly related to the thermal efficiency when the Brayton cycle pressure ratio and maximum temperature remain constant. The lower the entropy generation of the engine is, the higher the thermal efficiency. However, the secondary air system of the engine generates a large quantity of entropy compared to the components of the main flow channel, because the irreversible losses of the internal flow and heat exchange between the air system components generate considerable entropy within the system. In this study, the theoretical method is used to build entropy generation model for different characteristics of air system components during the aerothermal process. In this basis, an integrated model of the whole engine is introduced to identify the key components for entropy generation in the system environment. The results show that the labyrinth at outlet of unloading cavity is recognized as the one that generates the most entropy in the entire aeroengine system, and the total entropy generation of the system is highly related to this component. Besides, in the system environment, entropy generation is the sum of the local entropy generated by the components and the total entropy generated by mixing of airflows in each component. High local entropy generated by components does not necessarily result in a high system entropy production, and vice versa. Therefore, when the minimum system entropy generation is the design goal, the most critical operations for entropy generation should be identified according to the corresponding sensitivity and parameter variation range, and the design should be improved accordingly.

中文翻译：

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航空发动机系统环境中的熵生成和潜在抑制分析

从系统的角度来看，当布雷顿循环压力比和最高温度保持不变时，航空发动机的熵产生与热效率直接相关。发动机产生的熵越低，热效率越高。然而，发动机的二次空气系统与主流道的组件相比会产生大量的熵，因为内部流动的不可逆损失和空气系统组件之间的热交换会在系统内产生相当大的熵。本研究采用理论方法，针对空气系统组件在气动热过程中的不同特性建立熵生成模型。在此基础上，引入了整个引擎的集成模型，以识别系统环境中熵生成的关键组件。结果表明，卸荷腔出口处的迷宫被认为是整个航空发动机系统中产生熵最多的地方，系统总熵的产生与该部件高度相关。此外，在系统环境中，熵产生是组件产生的局部熵与各组件中气流混合产生的总熵之和。组件产生的高局部熵不一定会产生高系统熵，反之亦然。因此，当最小系统熵生成为设计目标时，