Abstract
The fluid force of labyrinth seals may cause unstable rotor vibrations in turbo-machineries. In this research, dynamic characteristics of face type labyrinth seals were measured by using a test rig. The rotor-bearing system was supported by soft cage springs, and it was excited using a magnetic bearing. Cross-coupled stiffness, direct damping and effective damping coefficient were calculated and evaluated as dynamic characteristics of the seals. As a result, cross-coupled stiffness increased, and direct damping decreased, when the rotating speed increased. Effective damping coefficient showed that the fluid force of the labyrinth seal stabilizes rotor vibration at bwer rotating speed, and it destabilizes rotor vibration at higher rotating speed.
