Session: 30-02 Damping evaluation and effect I

Paper Number: 82960

82960 - Gas Turbine Rotor Damper Lift-Off Study 

Gas turbine rotor system is subject to vibratory stresses due to excitations caused by various sources at high energy levels. To dissipate the energy that occurs in the rotating system, damping is induced internally or externally. Damping is achieved by having damper at the appropriate locations in the rotor system. The damper needs to have a provision to assemble in the rotor assembly, which is typically a split, facilitating the damper to wind and unwind in circumferential direction. The damper used in the rotating system needs to be an axisymmetric structure with any kind of cross-section, to achieve the required level of damping. As the damper is used at the interior locations of the rotor system, they need to build necessary preloading by itself, without any additional parts in such a way that the damper rotates with the rotor system during operation. In addition, the damper needs to have appropriate feature for axial retention. Damper design study is very vital in deciding the shape of the damper in such a way that it provides efficient damping and minimizing the vibratory stress while fulfilling the above stated requirement. Damper tends to detach from its supporting feature at some vibrating condition which is termed as damper lift-off. This lift-off behavior makes the damper design very complex. When the damper split region passes through the maximum lobe and minimum lobe position of any nodal diameter, the region near the split tends to lift-off from its support and behaves like a simply supported beam and cantilever beam respectively. A careful consideration of this damper lift-off phenomenon in damper design is key towards achieving a robust damper design. Finite element analysis is used to perform this design study. Various type of simulation techniques is followed in performing necessary design checks resulting in assuring design robustness. This paper is intended to describe the steps followed in performing damper design study using finite element analysis.

Presenting Author: Manoharan Sambandam Baker Hughes

Presenting Author Biography: Mechanical engineering working on Gas Turbine Engineering.

Authors:

Manoharan Sambandam Baker Hughes
Abhimanyu S Baker Hughes
Babu Santhana Gopalakrishnan Baker Hughes
Leonardo Tognarelli Baker Hughes
Guido Peano Baker Hughes