Numerical simulations of aeroelastic instabilities in a turbine-blade cascade by a modified Van der Pol model at running excitation

Abstract

The onset and spread of flutter in a turbine blade cascade are numerically studied. Due to the application of the reduced-cascade model consisting of simple elements (springs, rigid bodies, linear dampers) and aeroelastic forces introduced by the analytical Van der Pol model, it is useful to study the dangerous states of vibration of such complicated turbine parts. This study examines aeroelastic instabilities of a 10-blade cascade at running excitation that arise due to wakes flowing from the stator blades to the rotating blades. Unlike our previous work, it brings a new definition of the Van der Pol model of self-excitation that is controlled by relative inter-blade motion of neighbouring blades.