Experimental Study on Dynamic Characteristics of a Geared Turbo Fan Engine Rotor System

Because of some significant merits like high efficiency and low pollution, the geared turbo fan (GTF) engine has attracted wide attention in recent years. However, extra gearbox between the fan rotor and low-pressure (LP) turbine rotor introduces additional coupling effects, resulting in more complicated rotor dynamic characteristics. Thus, it is very important and meaningful to study these dynamic characteristics for the structural design and vibration control of the GTF engine rotor system. For this objective, some experimental cases on a lab GTF engine rotor system are studied in this paper. Firstly, the configuration of the lab GTF engine rotor system is introduced, and then experimental equipment and plan are shown. After that, dynamic testing for the critical speed, mode shape and dynamic response of the lab GTF engine rotor system is implemented. Experimental results demonstrate that the first three critical speeds of the lab GTF engine rotor system are 2356 r/min, 4606 r/min and 6318 r/min respectively corresponding to different mode shapes. With the rise of the rotating speed from 0 to 5000 r/min, both response amplitudes of the fan and turbine disks increase, and get maximum results at the second-order critical speed (4606 r/min).