Unsteady Flow Phenomena in Tandem Blade Multi-Stage Axial Compressors

对串联叶片进行的很少的研究表明，它们在涡轮压缩机和风机中的各种应用方式具有很高的潜力。接下来的步骤是研究其在单级和多级环境下的空气动力学行为，以发展对串联叶片的基本知识和设计相关性。这尤其适用于涡轮在非定常工况下运行的情况。到目前为止，时间依赖行为还没有得到深入的评估。因此，该项目旨在帮助理解在旋转机械布置环境中考虑摩擦损失的边界层内随时间变化的三维流动现象。在一台旋转多级低速压气机上实现了非定常流体动力学的研究，这对未来的创新涡轮机械设计具有代表性。重点研究了端壁附近区域的二次流现象以及动、静叶片排之间的相互作用。遵循整体方法，该项目包括实验和数值工作。该项目是继前FVV项目“压气机叶栅中串联叶片的空气动力学”（AIF-Nr）之后开展的。17454)，并提供了关于涡轮机械中串联叶片的流动物理的互补结果。这种知识的基本增长来自于从简化的级联实验到多级涡轮机械环境的研究的预期过渡，这使得衍生出串联压气机翼型气动性能的新模型成为可能。

The very few research research that were conducted on tandem vanes indicates the high potential regarding their various ways of application within turbo compressors and fans. The consequent step to develop essential knowledge and design correlations on tandem blades is to investigate its aerodyamic behavior in a single and multistage environment. In particular, this applies when the turbomachine is operating under unsteady condition. Until now, the time dependent behavior was not assessed in depth. Therefore, the project aims at contributing to the understanding of the time-dependent, three-dimensional flow phenomena under consideration of friction losses within the boundary layers occuring in the environment of rotating machine arrangement.The investigation of the unsteady fluid dynamics is realized on a rotating, multi-stage low-speed compressor rig that is representative for future innovative turbomachinery designs. Focus is set on secondary flow phenomena in regions adjacent to the endwalls and the mutual interactions of the rotor and stator blade rows. Following an holistic approach, this project encompasses both experimental and numerical work. This project is succeeding the former FVV project "aerodynamics of tandem vanes in a compressor cascade" (AIF-Nr. 17454) and delivers complementary results regarding the flow physics of tandem vanes in turbomachinery. This fundamental growth in knowledge results from the intended transition from simplified cascade experiments to investigations in multi-stage turbomachinery environment which allows the derivation of new models for the aerodynamic performance of tandem compressor airfoils.