Research Papers: Gas Turbines: Structures and Dynamics

Dynamic Characterization of an Integral Squeeze Film Bearing Support Damper for a Supercritical Co2 Expander

[+] Author and Article Information
Bugra Ertas

Mechanical Systems,
GE Global Research Center,
Niskayuna, NY 12308

Adolfo Delgado

Mechanical Engineering Department,
Texas A&M University,
College Station, TX 77843

Jeffrey Moore

Machinery Section,
Southwest Research Institute,
San Antonio, TX 78238

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 3, 2017; final manuscript received August 8, 2017; published online November 14, 2017. Editor: David Wisler.

J. Eng. Gas Turbines Power 140(5), 052501 (Nov 14, 2017) (9 pages) Paper No: GTP-17-1261; doi: 10.1115/1.4038121 History: Received July 03, 2017; Revised August 08, 2017

The present work advances experimental results and analytical predictions on the dynamic performance of an integral squeeze film damper (ISFD) for application in a high-speed super-critical CO2 (sCO2) expander. The test campaign focused on conducting controlled orbital motion mechanical impedance testing aimed at extracting stiffness and damping coefficients for varying end seal clearances, excitation frequencies, and vibration amplitudes. In addition to the measurement of stiffness and damping, the testing revealed the onset of cavitation for the ISFD. Results show damping behavior that is constant with vibratory velocity for each end seal clearance case until the onset of cavitation/air ingestion, while the direct stiffness measurement was shown to be linear. Measurable added inertia coefficients were also identified. The predictive model uses an isothermal finite element method to solve for dynamic pressures for an incompressible fluid using a modified Reynolds equation accounting for fluid inertia effects. The predictions revealed good correlation for experimentally measured direct damping, but resulted in grossly overpredicted inertia coefficients when compared to experiments.

Copyright © 2018 by ASME
Your Session has timed out. Please sign back in to continue.


Kalra, C. J. , Hofer, D. , Sevincer, E. , Moore, J. , and Brun, K. , 2014, “ Development of High Efficiency Hot Gas Turbo-expander for Optimized CSP Supercritical CO2 Power Block Operation,” The Fourth International Symposium—Supercritical CO2 Power Cycles (sCO2), Pittsburgh, PA, Sept. 9–10, pp. 1–11. http://citeseerx.ist.psu.edu/viewdoc/download?doi=
Hofer, D. , 2016, “sCO2 Power Cycle Path Forward,” IGTI Turbo Expo, Seoul, South Korea, June 13–17.
Magge, N. , 1975, “ Philosophy, Design, and Evaluation of Soft-Mounted Engine Rotor Systems,” J. Aircr., 12(4), pp. 318–324. [CrossRef]
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. [CrossRef]
Memmott, E. A. , 1992, “ Stability of Centrifugal Compressors by Applications of Tilt Pad Seals, Damper Bearings, and Shunt Holes,” IMechE Fifth International Conference on Vibrations in Rotating Machinery, Bath, UK, Sept. 7–10, pp. 99–106.
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.
Della Pietra, L. , 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.
Taylor, D. L. , and Fehr, V. S. , 1982, “ Analysis and Design of Segmented Dampers for Rotor Dynamic Control,” J. Lub. Tech., 104(1), pp. 84–90. [CrossRef]
Locke, S. R. , and Faller, W. , 1999, “ Recycle Gas Compressor Designed for High Unbalance Tolerance and Stability,” 32nd Turbomachinery Symposium, Houston, TX, Sept. 8–11, pp. 137–144. https://oaktrust.library.tamu.edu/handle/1969.1/163297
Ertas, B. , Cerny, V. , Kim, J. , and Polreich, V. , 2015, “ Stabilizing a 46 MW Multistage Steam Turbine Using Integral Squeeze Film Bearing Support Dampers,” ASME J. Eng. Gas Turbines Power, 137(5), p. 052506. [CrossRef]
de Santiago, O. , San Andrés, L. , and Oliveras, J. , 1999, “ Imbalance Response of a Rotor Supported on Open-Ends, Integral Squeeze Film Dampers,” ASME J. Eng. Gas Turbines Power, 121(4), pp. 718–724. [CrossRef]
De Santiago, O. , and San Andrés, L. , 1999, “Imbalance Response and Damping Force Coefficients of a Rotor Supported on End Sealed Integral Squeeze Film Dampers,” ASME Paper No. 99-GT-203.
De Santiago, O. , and San Andrés, L. , 2000, “Dynamic Response of a Rotor-Integral Squeeze Film Damper to Couple Imbalances,” ASME Paper No. 2000-GT-0388.
San Andrés, L. , 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. [CrossRef]
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.
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,” EDF/Pprime Poitiers Workshop, Poitiers, France, Oct. 6–7, pp. 1–20.
Delgado, A. , Ertas, B. H. , Drexel, M. , Vaninni, G. , and Naldi, L. , 2010, “ A Component Level Test Rig for Dynamic Characterization of Oil Lubricated Bearings Using Different Input Excitations,” 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery (ISROMAC), Honolulu, HI, Apr. 4–7, Paper No. ISROMAC13-2010.
Delgado, A. , and San Andrés, L. , 2010, “ A Model for Improved Prediction of Force Coefficients in Grooved Squeeze Film Dampers and Grooved Oil Seal Rings,” ASME J. Tribol., 132(3), p. 032202. [CrossRef]
San Andrés, L. , and Delgado, A. , 2012, “ A Novel Bulk-Flow Model for Improved Predictions of Force Coefficients in Grooved Oil Seals Operating Eccentrically,” ASME J. Eng. Gas Turbines Power, 134(5), p. 052509. [CrossRef]
San Andrés, L. , and Seshagiri, S. , 2013, “ Damping and Inertia Coefficients for Two End Sealed Squeeze Film Dampers With a Central Groove: Measurements and Predictions,” ASME J. Eng. Gas Turbines Power, 135(11), p. 112503. [CrossRef]
Hassini, M. H. , Arghir, M. , and Frocot, M. , 2012, “ Comparison Between Numerical and Experimental Dynamic Coefficients of a Hybrid Aerostatic Bearing,” ASME J. Eng. Gas Turbines Power, 134(12), p. 122506. [CrossRef]
Gehannin, J. , Arghir, M. , and Bonneau, O. , 2009, “ Complete Squeeze-Film Damper Analysis Based on the “Bulk Flow” Equations,” Trib. Trans., 53(1), pp. 84–96. [CrossRef]


Grahic Jump Location
Fig. 6

Example dynamic excitation: 110 Hz at 0.75 mils peak vibration amplitude backward whirl

Grahic Jump Location
Fig. 5

Experimental setup

Grahic Jump Location
Fig. 4

Sunshot expander integral squeeze film damper test article

Grahic Jump Location
Fig. 3

2π squeeze film damper configurations versus ISFD

Grahic Jump Location
Fig. 2

Sunshot expander flexure pivot bearing w/ISFD

Grahic Jump Location
Fig. 1

Sunshot sCO2 14 MW 27 krpm expander

Grahic Jump Location
Fig. 7

Physical (linearized) representation of ISFD force coefficients

Grahic Jump Location
Fig. 8

Direct damping for various end seal clearances: 0.25 mil (6.35 μm) peak excitation amplitude

Grahic Jump Location
Fig. 9

Direct damping for various frequencies and vibration amplitudes and vibratory velocity

Grahic Jump Location
Fig. 10

Uncavitated versus cavitated ISFD

Grahic Jump Location
Fig. 11

Real part of the transfer function and added inertia force coefficients (0.25 mil p–p excitation amplitude)

Grahic Jump Location
Fig. 12

Integral squeeze film damper flow domain and boundary conditions used in numerical model

Grahic Jump Location
Fig. 13

Pressure versus flow rate: ISOVG32 @ 120F

Grahic Jump Location
Fig. 14

Top view of damper land showing velocity contour plot and flow streamlines. Steady-state CFD calculation using a commercial software. End seal clearance: 7.5 mils, supply pressure 20 psig.



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In