Unsteady Flow Phenomena in Tandem Blade Multi-Stage Axial Compressors

对串联叶片进行的极少数研究表明，它们在涡轮压缩机和风扇中的各种应用方式具有很高的潜力。发展串列叶片的基本知识和设计相关性的后续步骤是研究其在单级和多级环境中的气动特性。特别是，这适用于在不稳定条件下操作的涡轮机。到目前为止，时间依赖性行为没有进行深入评估。因此，本项目的目的是在考虑旋转机械布置环境中边界层内的摩擦损失的情况下，帮助理解与时间相关的三维流动现象。非定常流体动力学的研究是在一个旋转的多级低速压气机试验台上实现的，该试验台是未来创新压气机设计的代表。重点放在端壁附近区域的二次流现象以及转子和定子叶片排的相互作用上。该项目采用整体方法，包括实验和数值工作。该项目是前FVV项目“压气机叶栅中串列叶片的空气动力学”（AIF-Nr。17454），并提供了互补的结果，关于流动物理的串联叶片在涡轮。知识的这种基本增长是由于从简化叶栅实验到多级叶栅环境研究的预期过渡，这使得能够推导出串列式压气机翼型气动性能的新模型。

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.