VIBRATION RESPONSE ANALYSIS OF DUAL-ROTOR SYSTEM IN AERO-ENGINES

In order to study dynamic characteristics of a dual-rotor aero-engine, a similar dual-rotor system dynamic model is established. The influence of the high- and low-pressure rotor rotation speed on the vibration response of the co-rotating or counter-rotating dual-rotor system in aero-engine is analyzed combine with critical speed diagram, and the vibration characteristics are experimentally verified by dual-rotor test rig system. Both the simulation and experimental results reveal that in the critical speed diagram the total amplitude of the dual-rotor system increases, when the actual speed line gets closer to a level of critical speed curve. The rotor base frequency component corresponding to the critical speed increases, mean while the other rotor base frequency component changes little. The total amplitude of the dual-rotor system decreases when the actual speed line moves away from a level of critical speed curve. The rotor base frequency component corresponding to the critical speed decreases, mean while the other rotor base frequency component changes little. The total amplitude and both of the high- and low-pressure rotor base frequency component are substantially unchanged except the dual-rotor system crosses its critical speeds, when the entire actual speed line is away from the critical speed curve. In order to avoid the dual-rotor system failure caused by an out of range response, the actual speed line shouldn't approach the critical speed curves for a long time, when carrying out a dual-rotor system rotor dynamic experiment.