19th Asia-Pacific Vibration Conference (APVC2021)

421 / 2022-07-31 22:00:46

Studies on modal characteristics of GTF star gear-rotor system considering structural flexibility and gyroscopic moments

Frequency veering,modal characteristics,geared turbofan,gear dynamics

Taking an experiment platform of Geared Turbofan (GTF) aero-engine as the object, a dynamic model of star gear-rotor system is established to explore the coupling effect of star gear train and rotor on the modal characteristics. The flexibility of the main components including the shaft, ring, disk and diaphragm coupling are considered based on the beam-shell mixed element. Besides, the gyroscopic moments of the rotors are also taken into account, and the frequency veering behavior induced by the change of running speed is analyzed. The results show that the star gear train and the rotor are highly related in some modes, and the flexibility of the rotor has a great influence on the gear modes. In addition, when two modes in the Campbell diagram are close to each other, if one contains the bending mode of the fan rotor and the other contains the bending mode of the input rotor or low-pressure rotor, the frequency veering will occur.