Piezo-Electric Actuation of Rotor Blades in an Axial Compressor

Abstract

An actuation method for the experimental investigation of compressor rotor blade vibrations is demonstrated. Three blades of the first compressor stage in a two-stage low-speed axial-flow compressor have been equipped with piezo-electric actuators, i.e. macro fiber composites (MFC). For measuring the actuated blade vibrations, strain gages are used. The control system which has been developed within this project allows to pre-set a vibration amplitude of the blade tip. The transmission of the actuation voltage of up to 1000V into the rotor is accomplished by a slip ring. A slip ring is also used for transmitting the strain gage signals. The tests in the rotating machine show that the forces induced by MFCs are large enough to cause sufficiently strong vibrations. The signal quality of the data transmission via slip ring is high enough to operate the control unit that allows actuating the rotor blades up to a pre-defined vibration amplitude when matching the lower eigen modes of the blades