Flow phenomena in an annular stator compressor cascade with tandem blading and the influence of real geometries

• Applicant: Professor Dr.-Ing. Dieter Peitsch, since 1/2020
• Subject Area: Hydraulic and Turbo Engines and Piston Engines ; Fluid Mechanics
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 398359749

Within the proposed project, detailed investigations of a tandem cascade will determine the influence of the tip leakage flow on the flow field and the associated loss sources in an annular compressor cascade. The experimental setup allows for a study of the influence of the radial flow effects on the throughflow of highly loaded tandem stators in order to get a deeper understanding of the prevailing flow topology. First, the flow field of tandem vanes is to be investigated in detail without a tip gap and compared with the flow field of a conventional reference vane with regard to a desired static pressure increase or loss reduction. In a second step, a tandem cascade and the associated conventional reference vanes are equipped with a tip gap and the resulting flow fields are then tested experimentally at different tip-gap sizes. The gaps between the rotating and static components (between the rotor and the casing, stator and hub) which are necessarily present in the compressor as well as in the case of partial gap configurations (variable stator vanes - VSV) can lead to a significant loss increase. The understanding of the tip leackage flow topology is therefore of fundamental importance on the one hand for the prediction of losses and on the other hand for the development of loss-reducing measures. A specific analysis of the influence of the blade tip gap on the extent of the secondary flows within the flow passage takes place. Optimum accessibility and measuring equipment of the measurement section allows a targeted analysis of the influence of the blade tip gap on the extent of the secondary flows within the flow passage. In order to further illustrate the prevailing conditions in the real turbomachine, the hub is finally set in rotation below the blade tip. Thus the influence of the hub rotation on the flow field of tandem vanes and the previously detected loss sources can be determined for the first time. The main focus of the investigation is the interaction between the secondary flow components in the radial and axial gap of the tandem blade. The aim of the investigation is to estimate the effectiveness of tandem configurations for different application areas within the compressor.

• DFG Programme: Research Grants
• Ehemalige Antragstellerin: Dr.-Ing. Christine Tiedemann, until 12/2019