Investigation on Blade Flutter in Transonic Compressor with a Coupled Numerical Approach

A fluid-solid coupled approach for investigating blade flutter in a compressor under the parallel computation of aeroelasticity is presented. The unsteady flow field of rotor is studied by a CFD model of the entire compressor flowpath, coupled with a finite element model for the blades to identify modal shapes, natural frequencies, vibratory stress and the structural deformations. Interactions between fluid and structure are dealt with in a coupled manner, based on the interface exchange of information between the aerodynamic and structural model. The coupled computational results are presented and compared with experimental data. Blade variations and the way of these variations is related to vibratory stress amplitude are investigated. Transient responses of blade stress are provided to determine whether flutter occurs. This coupled method successfully predicts the flutter of a transonic rotor over range of operating conditions. The nonlinear behaviors of flow field, blade vibrations, and inter-blade phase angle are discussed.