Influence of interblade phase angle on the flutter of rotor blades

A numerical simulation method for turbomachinery bladings basing on energy method with interblade phase angle (IBPA) has been developed. The whole annular oscillating cascades have been modeled with each blade channel divided into the moveable region near the blade surface and the outer fixed region. The node displacements of finite element model, on the basis of computational structural dynamics (CSD), have been transferred to fluid interface grids with finite element interpolation algorithm. Reynolds-averaged Navier-Stokes(RANS)equations with k-ε turbulent model for closure have been solved for the whole annular oscillating cascades. At the design speed of NASA Rotor 67, the aerodynamic work in one oscillating period and the corresponding aerodynamic modal damping ratios of the whole annular cascades in different IBPA have been obtained. The effects of IBPA on the flutter of cascades have been determined on the basis of energy method. The results show that IBPA has significant influence on the flutter of rotor blades.