基于快响应压敏漆PSP和高频响Stereo-PIV实验测量的振荡来流下气膜冷却时空演变的研究

Up to now, most of the film cooling studies were performed with the mainstream flow being uniform and steady, however the actual flow condition in real aero-engines/gas turbines is usually unsteady or even featured with oscillated mainstream flow, which makes the film cooling out of function. In the present study, a Fast Pressure Sensitive Paint (Fast-PSP) technique will be used to record the time-resolved cooling effectiveness under oscillated flow condition, meanwhile a high-frequency Stereo Particle Image Velocimetry (Stereo-PIV) system will be applied to quantify the corresponding three-dimensional flow field. The objective of the present study is to explore the unsteady behaviors of film cooling, and the spatial and temporal evolution of the corresponding flow field as well as the effect of oscillating frequency and magnitude on the film cooling performance. Furthermore, advanced analysis methods, such as Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD), will be utilized to analyze the large dataset and elucidate the underlying physics pertinent to the evolution of large-scale vortex structure and their impact on the overall cooling performance. The research results of the present study will be highly valuable for the development of advanced film cooling technique for the sake of improving the cooling protection of turbine engines in the future.

目前，针对航空发动机/燃气轮机的气膜冷却研究主要集中在定常来流条件下，然而工程实际中的主流气体往往是非定常的，甚至还可能出现周期性振荡现象，致使高温部件的气膜冷却失效。为此，本项目将综合使用快响应压敏漆Fast-PSP和高频响Stereo-PIV技术分别测量振荡来流下的壁面气膜冷却效率和三维动态流场，探索振荡来流下的气膜冷却特性和复杂流场的时空演变规律，以及主流振荡频率和幅度对气膜冷却的影响。此外，本项目将综合运用本征正交分解POD和动力学模态分解DMD数据分析方法，揭示复杂涡系的时空演变及其对气膜冷却性能的影响。相关研究成果将为先进气膜冷却技术的发展提供重要的理论指导，具有重要的工程应用价值。