Effects of frequency mistuning on aeroelastic stability of transonic compressor

A full-annulus computational model for aerodynamic damping prediction based on energy method is demonstrated by the consideration of a transonic flutter test rotor to improve the understanding of the influence of frequency mistuning on aeroelastic stability of transonic compressor. The numerical analysis of alternate, random and linear frequency mistuning was performed in detail. The numerical results of rotor aerodynamic performance, flutter boundary and blade mode shape are respectively consistent with experimental results closely. According to the aerodynamic damping of tuned rotor under the different inter-blade phase angle (IBPA) and modes, it indicates that blade aerodynamic damping is affected greatly by IBPA, especially for the first bending mode. The blade aerodynamic damping is most sensitive to IBPA. The further investigation on various frequency mistuning modes show that, the existence of mistuning weaken the effect of IBPA on blade average aerodynamic damping. Especially, the average aerodynamic damping of all blades at the most unstable condition increases about 7 to 11 times. On the contrary, it decreases about 50% at the most stable condition. There are significant differences among the aerodynamic damping of each mistuned blade which is affected obviously by the blade local mistuned mode and mistuning amount.