Study of dry-friction damping effect on two simplified models of flutter oscillations
Dry-friction damping effect to reduction of self-excited vibrations due to aero-elastic instability is studied on numerical reduced model of rotating turbine wheel with 30 blades. The aerodynamic excitation arises from the spatially periodical flow of steam through the stator blades cascade. Dry friction contact damping is considered as one of the very effective methods for self-excited “flutter” vibrations. The study is oriented on the narrow frequency range and therefore the blades are modelled as systems with one degree of freedom (DOF). The selfexcited aero-elastic forces of blades are described by two different types of Van der Pol model. It is shown for both self-excitation models that the dry friction forces needed for suppression of dangerous flutter vibrations strongly depends on the complexity of modes and also on the mutual positions of excitation forces to damping elements.
KeywordsFlutter oscillations of turbine blades dry friction damping of vibration modes nodal diameters
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This work has been supported by the grant project of the Czech Science Foundation No. 19-02288J “Robust reduced-order modeling of fluid-structure interaction problems”.
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