Aeroelastic stability analysis of rotor blades under multi-row environment

Conventional blade flutter analysis is normally based on an isolated blade row model, the influence of multi-row aerodynamic coupling on blade flutter characteristics can't be ignored when rotor-stator gaps decrease due to aeroengine compact requirements. A fluid-structure coupled simulation for a 1.5stage HPC was conducted with a self-developed algorithm to analyze the influence of upstream and downstream blade rows on rotor blade flutter characteristics. Aiming at a typical operation condition, rotor blades' aeroelastic stability analyses were performed with an isolated rotor model, an IGV-rotor model, a rotor-stator one and an IGV-rotor-stator one, respectively. The results showed that the shock wave vibration influences the flutter stability significantly; there are reflection and superposition of unsteady pressure waves under the multi-row environment, the amplitude and phase of unsteady pressures on the rotor blade surface are changed obviously and furthermore the blade aeroelastic stability is changed; multi-row interferences raise the aerodynamic damping of rotor blade, especially, when the upstream and downstream blade rows act simultaneously, the damping value increases by nearly 732.7%.