<p class="MsoBodyTextIndent"><i>Severe resonant vibration is one of the main roots of turbomachinery blades failure. Forced response issues arise when the blades work in non-uniform flow fields. As a result unsteady aerodynamic pressures occur on the surfaces of the blade. If the frequency of the aerodynamic excitation matches an eigenfrequency of the blade, the vibration level may considerably increase and a drop in the life-cycle of the component could be entailed. The resonant vibration conditions could be identified at the design level by means of the Campbell diagram. Unfortunately, it is not possible to avoid all the resonant conditions and, under certain circumstances, two eigenmodes may be excited at the same shaft angular speed (bi-modal excitation). Hence, the mitigation of vibration has always been one of the utmost importance for turbomachinery designers. Moreover an active damping system based on piezoelectric (PZT) actuators, that is capable of tuning its behavior according to the resonant excitation, may be considered very attractive. In this work the forced response of a fan rotor blade, due to a stationary inlet flow distortion resulting from the presence of upstream struts, is taken into account. Some resonant conditions, which occur at different shaft speed, have been analyzed by means of Computational Fluid Dynamics (CFD) and Finite Element Analysis (FEA) simulations. Thereafter a novel approach based on a proper distribution of the potential supplied to the electrodes of each PZT pairs, in order to maximize the damping efficiency, is here applied to the case of an actual turbomachinery blade. The outcomes show that the proposed system is able to efficiently damp each resonant excitation and enhance the structural integrity of the blade. </i></p>

High-Efficiency Active Damping on a Fan Rotor Blade in Case of Resonant Vibrations by Means of Pzt Actuators

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

Turbo Expo 2021

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