A 46 MW 5500 rpm multistage single casing utility steam turbine experienced strong subsynchronous rotordynamic vibration of the first rotor mode; preventing full load operation of the unit. The root cause of the vibration stemmed from steam whirl forces generated at secondary sealing locations in combination with a flexible rotor-bearing system. Several attempts were made to eliminate the subsynchronous vibration by modifying bearing geometry and clearances, which came short of enabling full load operation. The following paper presents experimental tests and analytical results focused on stabilizing a 46 MW 6230 kg utility steam turbine experiencing subsynchronous rotordynamic instability. The paper advances an integral squeeze film damper (ISFD) solution, which was implemented to resolve the subsynchronous vibration and allow full load and full speed operation of the machine. The present work addresses the bearing-damper analysis, rotordynamic analysis, and experimental validation through waterfall plots, and synchronous vibration data of the steam turbine rotor. Analytical and experimental results show that using ISFD improved the stability margin by a factor of 12 eliminating the subsynchronous instability and significantly reducing critical speed amplification factors. Additionally, by using ISFD the analysis showed significant reduction in interstage clearance closures during critical speed transitions in comparison to the hard mounted tilting pad bearing configuration.

References

References
1.
Magge
,
N.
,
1975
, “
Philosophy, Design, and Evaluation of Soft-Mounted Engine Rotor Systems
,”
J. Aircr.
,
12
(
4
), pp.
318
324
.10.2514/3.44450
2.
Vance
,
J.
, and
Royal
,
A.
,
1975
, “
High-Speed Rotor Dynamics—An Assessment of Current Technology for Small Turboshaft Engines
,”
J. Aircr.
,
12
(
4
), pp.
295
305
.10.2514/3.44447
3.
Memmott
,
E. A.
,
1992
, “
Stability of Centrifugal Compressors by Applications of Tilt Pad Seals, Damper Bearings, and Shunt Holes
,”
IMechE 5th International Conference on Vibrations in Rotating Machinery, Bath
, UK, Sept. 7–10, pp.
99
106
.
4.
Memmott
,
E. A.
,
2010
, “
Application of Squeeze-Film Dampers to Centrifugal Compressors
,”
28th Machinery Dynamics Seminar
(CMVA2010), Ville, QC, Canada, Oct. 27–29, Paper No. CMVA2010-15, pp.
115
129
.
5.
Zeidan
,
F. Y.
,
Andres
,
L. S.
, and
Vance
,
J. M.
,
1996
, “
Design and Application of Squeeze Film Dampers in Rotating Machinery
,”
25th Turbomachinery Symposium
, Houston, TX, Sept. 17–19, pp.
169
188
.
6.
Leader
,
M. E.
,
Whalen
,
J. K.
, and
Grey
,
G. G.
,
1995
, “
The Design and Application of a Squeeze Film Damper Bearing to a Flexible Steam Turbine Rotor
,”
24th Turbomachinery Symposium
, College Station, TX, pp.
49
58
.
7.
Edney
,
S. L.
, and
Nicholas
,
J. C.
,
1999
, “
Retrofitting a Large Steam Turbine With a Mechanically Centered Squeeze Film Damper
,”
27th Turbomachinery Symposium
, Houston, TX, pp.
29
40
.
8.
Kuzdzal
,
M. J.
, and
Hustak
,
J. F.
,
1996
, “
Squeeze Film Damper Bearing Experimental vs. Analytical Results for Various Damper Configurations
,”
25th Turbomachinery Symposium
, College Station, TX, pp.
57
70
.
9.
Kanki
,
H.
,
Kaenko
,
Y.
,
Kurosawa
,
M.
, and
Yamamoto
,
T.
,
1998
, “
Prevention of Low-Frequency Vibration of High-Capacity Steam Turbine Units by Squeeze Film Damper
,”
ASME J. Eng. Gas Turbines Power
,
120
(2), pp.
391
396
.10.1115/1.2818135
10.
Locke
,
S. R.
, and
Faller
,
W.
,
1999
, “
Recycle Gas Compressor Designed for High Unbalance Tolerance and Stability
,”
32nd Turbomachinery Symposium
, Houston, TX, pp.
137
144
.
11.
De Santiago
,
O.
,
Andrés
,
L. S.
, and
Oliveras
,
J.
,
1999
, “
Imbalance Response of a Rotor Supported on Open-Ends, Integral Squeeze Film Dampers
,”
ASME J. Gas Turbines Power
,
121
(
4
), pp.
718
724
.10.1115/1.2818532
12.
De Santiago
,
O.
, and
Andrés
,
L. S.
, 1999, “
Imbalance Response and Damping Force Coefficients of a Rotor Supported on End Sealed Integral Squeeze Film Dampers
,”
ASME
Paper No. 99-GT-203. 10.1115/99-GT-203
13.
De Santiago
,
O.
, and
Andrés
,
L. S.
, 2000, “
Dynamic Response of a Rotor-Integral Squeeze Film Damper to Couple Imbalances
,”
ASME
Paper No. 2000-GT-0388. 10.1115/2000-GT-0388
14.
Andrés
,
L. S.
, and
De Santiago
,
O.
,
2003
, “
Imbalance Response of a Rotor Supported on Flexure Pivot Tilting Pad Journal Bearings in Series With Integral Squeeze Film Dampers
,”
ASME J. Eng. Gas Turbines Power
,
125
(4), pp.
1026
1032
.10.1115/1.1492831
15.
Agnew
,
J.
, and
Childs
,
D.
,
2012
, “
Rotordynamic Characteristics of a Flexure Pivot Pad Bearing With an Active and Locked Integral Squeeze Film Damper
,”
ASME
Paper No. GT2012-68564. 10.1115/GT2012-68564
16.
Hibner
,
D. H.
,
1975
, “
Dynamic Response of Viscous-Damped Multi-Shaft Jet Engines
,”
J. Aircr.
,
12
(
4
), pp.
305
312
.10.2514/3.44448
17.
Gunter
,
E. J.
,
1977
, “
Design of Nonlinear Squeeze Film Dampers for Aircraft Engines
,”
J. Lubr. Technol.
,
99
(
1
), pp.
57
64
.10.1115/1.3452990
18.
Taylor
,
D. L.
, and
Fehr
,
V. S.
,
1982
, “
Analysis and Design of Segmented Dampers for Rotor Dynamic Control
,”
J. Lubr. Technol.
,
104
(
1
), pp.
84
90
.10.1115/1.3253168
19.
Delgado
,
A.
,
Cantanzaro
,
M.
,
Mitanitonna
,
N.
, and
Gerbet
,
M.
,
2011
, “
Identification of Force Coefficients in a 5-Pad Tilting Pad Bearing With an Integral Squeeze Film Damper
,”
10th EDF/Pprime Poitiers Workshop
, Poitiers, France, Oct. 6–7.
20.
Della Pietra
,
L.
, and
Adiletta
,
G.
,
2002
, “
The Squeeze Film Damper Over Four Decades of Investigations. Part I: Characteristics and Operating Features
,”
Shock Vib. Dig.
,
34
(
1
), pp.
3
26
.
21.
Pietra
,
L. D.
, and
Adiletta
,
G.
,
2002
, “
The Squeeze Film Damper Over Four Decades of Investigations. Part II: Rotordynamic Analyses With Rigid and Flexible Rotors
,”
Shock Vib. Dig.
,
34
(
2
), pp.
97
126
.
22.
Gunter
,
E. J.
,
1978
, “
Optimum Bearing Support Damping for Unbalance Response and Stability of Rotating Equipment
,”
ASME J. Eng. Power
,
100
(
1
), pp.
89
94
.10.1115/1.3446331
23.
Alford
,
J.
,
1965
, “
Protecting Turbomachinery From Self-Excited Rotor Whirl
,”
ASME J. Eng. Power
,
87
(
4
), pp.
333
343
.10.1115/1.3678270
24.
Childs
,
D.
, and
Vance
,
J. M.
,
1997
, “
Annular Gas Seals and Rotordynamics of Compressors and Turbines
,”
26th Turbomachinery Symposium
, Houston, TX, pp.
201
220
.
25.
Edney
,
S. L.
, and
Lucas
,
G. M.
,
2000
, “
Designing High Performance Steam Turbines With Rotordynamics as a Prime Consideration
,”
29th Turbomachinery Symposium
, Houston, TX, pp.
205
223
.
26.
Bachschmid
,
N.
,
Pennacchi
,
P.
, and
Vania
,
A.
,
2007
, “
Some Results in Steam Whirl Analysis
,” 12th IFToMM World Congress, Bensancon, France, June 18–21, pp.
201
220
.
27.
Hirano
,
T.
,
Takashi
,
S.
,
Sakakida
,
H.
,
Uchida
,
T.
,
Tsutsui
,
M.
, and
Ikeda
,
K.
,
2008
, “
Evaluation of Rotordynamic Stability of a Steam Turbine Due to Labyrinth Seal Forces
,”
J. Power Energy Syst.
,
2
(
3
), pp.
945
955
.10.1299/jpes.2.945
28.
Dimarogonas
,
A.
, and
Gomez-Mancilla
,
J. C.
,
1994
, “
Flow-Excited Turbine Rotor Instability
,”
Int. J. Rotating Mach.
,
1
(
1
), pp.
37
51
.10.1155/S1023621X94000047
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