MISTUNING AND COUPLING EFFECTS IN TURBOMACHINERY BLADINGS

A numerical method has been developed to study the effects of structural mistuning on the aeroelastic behavior of turbomachinery cascades. The approach used is the combination of a modal reduction technique, where the structural properties of each blade are represented by only a few eigenmodes, with a linearized Euler method for the aerodynamic calculations. The method is validated and applied to two test cases, comprising of a high pressure turbine rotor and a transonic compressor rotor. Both are representative of modern turbomachinery designs. The results of the validation confirm the ability of the present method to accurately capture the dominant effects that influence the aeroelastic behavior of the cascades. Further case studies are performed to assess the influence of alternating and random mistuning on the resonant response amplitudes and on the aeroelastic stability.