The Blade Profile Orientations Effects on the Aeromechanics of Multirow Turbomachines

Abstract

The aerodynamic damping calculations for turbomachinery blade aeromechanics applications are typically carried out in an isolated blade row. The aerodynamic damping of vibrating blades, however, can be significantly influenced by the presence of neighboring blade rows. A highly efficient frequencydomain method is used to investigate the multirow effects on the blade row aerodynamic damping of a compressor and turbine. Depending on the blade profile orientations, the flow reflection effects from adjacent blade rows can significantly alter both unsteady pressure amplitudes and phase angles. Therefore, the blade aerodamping might increase or decrease depending on the stabilizing or destabilizing effects of the unsteady pressure changes. In the case of the compressor, the downstream stator significantly changes the unsteady pressure distribution on the rotor thus, affects the rotor aerodamping. In the turbine case, the upstream stator has a major effect on the aerodamping, while the downstream stator does not significantly change the rotor aerodamping.