[en] Assessing the aeroelastic behavior of blades is a crucial step in modern jet engines design. In recent years, efforts have been done to build whole assembly models of fan flutter. Flutter results from a competition of complex phenomena such as shock-wave oscillation, boundary-layer separation and acoustic reflections. To identify the mechanism triggering the instability, a radial decomposition strategy based on a linear superposition principle is applied to a transonic fan. The geometry consists of the low-pressure part of the engine, namely the air intake, the fan, the outlet guide vane and the engine section stators. Experimentally, flutter was encountered in the first bending mode at part speed. 3D URANS aeroelastic computations are able to reproduce the flutter instability. The modeshape is then radially split into ten independent panels. One aeroelastic computation is performed for each panel, giving the radial contribution to the global damping coefficient. The most destabilising contribution is found at 80% span, below the least stable radial level (90% span). These results indicate that some radial migration of the pressure fluctuations is responsible for stall flutter.
Disciplines :
Aerospace & aeronautics engineering
Author, co-author :
Rendu, Quentin; Vibration University Technology Center Mechanical Engineering Department Imperial College London, London, UK
Stapelfeldt, Sina; Vibration University Technology Center Mechanical Engineering Department Imperial College London, London, UK
Salles, Loïc ; Université de Liège - ULiège > Aérospatiale et Mécanique (A&M) ; Vibration University Technology Center Mechanical Engineering Department Imperial College London, London, UK
Vahdati, Mehdi; Vibration University Technology Center Mechanical Engineering Department Imperial College London, London, UK
Language :
English
Title :
Identification of low speed fan flutter trigger through radial decomposition of the modeshape
Publication date :
17 November 2019
Event name :
International Gas Turbine Congress
Event place :
Tokyo, Japan
Event date :
2019
Audience :
International
Main work title :
Proceedings of the International Gas Turbine Congress 2019 Tokyo
