H. Kanki et al., PREVENTION OF LOW-FREQUENCY VIBRATION OF HIGH-CAPACITY STEAM-TURBINE UNITS BY SQUEEZE-FILM DAMPER, Journal of engineering for gas turbines and power, 120(2), 1998, pp. 391-396
The cause of the low-frequency vibration (subsynchronous vibration) of
a high-pressure turbine was investigated by the analytical study and
vibration exciting lest for the actual machine in operation. From the
results, it is found that the low-frequency vibration is caused by the
decrease of the rotor system damping at high-loading operating condit
ions. As a countermeasure, a squeeze-film damper is designed in order
to increase the damping of the rotor system. After the verification te
st of the squeeze-film damper's capability in the workshop, it was ins
talled on the actual turbine. Vibration exciting tests for the high-pr
essure turbine under the actual operating conditions were carried out.
These field tests confirmed that the damping of the rotor system was
increased as expected in the design and consequently the low-frequency
vibrations disappeared completely under all operating conditions.