Effect of asymmetric shroud gap and shroud friction coefficient on vibration response of shrouded blades

Abstract

Based on the problem of shroud gap and shroud friction having impact on the blade collision vibration, a three-blade dynamic analysis model considering shroud friction and asymmetric gap is established in the present work. In order to study the effect of asymmetric gap and shroud friction coefficient on the vibration of the twisted shrouded blade in practice. The differential equations of shroud oblique collision between the twisted shrouded blade and adjacent blades were established, and a nonlinear Hertz contact force and an exponentially decaying friction model were used to describe the shroud contact collision force and friction, respectively. Numerical simulation and experiment are used to verify the vibration response of the blade under different gaps. The results show that the shroud movement under the asymmetric gap is more complicated than symmetric gap. The presence of shroud friction causes the passive blades to enter a cyclic motion. And shroud friction coefficient increases will decrease the amplitude of the blade.

Self-shrouded torsional blade model equivalence and blade vibration response analysis

“…When the blade vibrates, the working surfaces of the shroud can collide and rub against each other to absorb the vibration energy. [1][2][3] The contact collision process of the self-shrouded blade is very complex and has typical nonlinear characteristics. The torsional blade structure is complex, which is difficult to calculate by the traditional method and the calculation time is long, so the torsional blade needs to be simplified accordingly.…”