Aeroelastic effect of declining hub to tip ratios on the low-pressure compressor of future UHBR engines

• Applicants: Professor Dr.-Ing. Jens Friedrichs; Professor Dr.-Ing. Jörg Seume
• Subject Area: Hydraulic and Turbo Engines and Piston Engines
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 290312636

Aim of the project is the identification of key sensitivities, which will result in new or enhanced aerodynamic and aeroelastic interactions of future large bypass ratios of engines which are achieved through reduced hub-to-tip ratios. The approach is to assess the aeroelastic sensitivity of the first compressor stage with respect to the excitation by UHBR fan wakes in unprecedented quality based on an integrated investigation of various fan, duct- and IGV variations. From this research task, the following sub-goals are derived: a) Aerodynamic characterization and detailed study of three-dimensional flow structure of the inflow to the low-pressure compressor for UHBR fan stages with low hub-to-tip ratiofocussing on the hub near flow regime and secondary flow structures. b) Consideration of the rotor-cavity leakage flow. c) Consideration of the periodic unsteady interaction between fan rotor outlet, IGV and LPC-rotor.d) New Strategies to avoid increased forced-response and self-excitation of the blades in the front core engine due to typical secondary flow effects. d) e) Typical excitation sources are evaluated taking into account current trends in the development of aircraft engines, for example UHBR fans and geared turbofans and turboprops after their aeroelastic excitation and cataloged.

• DFG Programme: Research Grants