Investigation of Flutter Characteristics of a Wide-chord High-speed Transonic Fan

Flutter is a serious threat to the operation safety of aero-engines, gas turbines, etc., but the relationship between the flutter stability and the flow structure is not yet clear. In this paper, the flutter characteristic of the first bending mode of a wide-chord sweep high-speed transonic fan rotor is investigated by the traveling wave method (TWM) and the influence coefficient method (ICM), and the characteristics from choke point to the near stall point at 100% speed are calculated. When ICM is used, the influence of computational domain with different passages on aerodynamic damping is analyzed, and compared with the results obtained by TWM. The relationship between the flow structure and the aerodynamic damping on the blade surface is studied, aiming to improve the understanding of the flutter mechanism. The result shows that both ICM and TWM can make a good prediction of the aerodynamic damping. In terms of effect of flow structure on aerodynamic damping, shock wave, separation caused by the interaction of shock and boundary, tip leakage flow, and unsteady pressure fluctuations near the tip region of suction side leading edge have a great influence on the aerodynamic damping distribution. © 2021, Science Press. All right reserved.