Coupled vibrations of gas turbine shrouded blades

A model is proposed for analyzing the vibration characteristics of shrouded blades and their calculation method by employing a wave propagation theory and modal synthesis technology coupled with a finite element method from the view point is possible not only to conduct frequency modulation of the shrouded blades of a gas turbine, but also to utilize the friction effects between them to dissipate energy, thereby attaining the aim of vibration alleviation. As shrouded blades have been widely used in the design of high-speed turbomachinery, such as modern gas turbines and steam turbines. The shrouded blades forming an integral whole in a centrifugal force field, so the vibration characteristics of the whole ring of blades are different from those of a single isolated blade. This makes it essential to take into account the integral effect of blade shrouds. Conclusion from the calculation examples and engineering application shows that the above approach is valid and correct along with the possibility of considerably reducing the scale of calculation and analysis, and points out that it is necessary to take into consideration the coupled effect of the whole ring of blades while the dynamic characteristics of shrouded blades are being analysed.