Experiments and field applications have demonstrated that multiple-pocket gas damper seals effectively eliminate subsynchronous vibration and attenuate imbalance response at the critical speeds in turbomachinery. A one-control volume, turbulent bulk-flow model for the prediction of the seal leakage and rotordynamic force coefficients of centered multiple-pocket damper seals is hereby detailed. Comparisons of numerical predictions with experimental force coefficients for a four-pocket damper seal are presented. The bulk-flow model and experiments indicate the seal direct stiffness and damping force coefficients are insensitive to journal speed while the cross-coupled stiffnesses increase slightly. However, the current model overpredicts the direct damping coefficient and underpredicts the direct stiffness coefficient for increasing test pressure ratios. Computed results show that the force coefficients of multiple-pocket gas damper seals are also functions of the rotor excitation frequency.
Issue Section:
Research Papers
Topics:
Dampers,
Damping,
Flow (Dynamics),
Stiffness,
Excitation,
Leakage,
Pressure,
Rotors,
Turbomachinery,
Turbulence,
Vibration
1.
Alford J. S., 1965, “Protecting Turbomachinery From Self-Excited Rotor Whirl,” ASME Journal of Engineering for Power, Oct., pp. 333–344.
2.
Childs
D. W.
1978
, “The Space Shuttle Main Engine High-Pressure Fuel Turbopump Rotordynamic Instability Problem
,” ASME Journal of Engineering for Power
, Vol. 100
, pp. 48
–57
.3.
Childs
D. W.
Scharrer
J. K.
1986
, “An Iwatsubo-Based Solution for Labyrinth Seals: Comparison to Experimental Results
,” ASME Journal of Engineering for Gas Turbines and Power
, Vol. 108
, pp. 325
–331
.4.
Childs, D. W., 1993, Turbomachinery Rotordynamics: Phenomena, Modeling, & Analysis, Wiley, New York, p. 300.
5.
Childs
D. W.
Elrod
D.
Hale
K.
1989
, “Annular Honeycomb Seals: Test Results for Leakage and Rotordynamic Coefficients; Comparisons to Labyrinth and Smooth Configurations
,” ASME JOURNAL OF TRIBOLOGY
, Vol. 111
, pp. 293
–301
.6.
Childs, D. W., Elrod, D., and Ramsey, C., 1990, “Annular Honeycomb Seals: Additional Test Results for Leakage and Rotordynamic Coefficients,” Proceedings of the Third International Conference on Rotordynamics in IFToMM, Lyon, France, pp. 303–312.
7.
Doyle, H., 1980, “Field Experience with Rotordynamic Instability in High-Performance Turbomachinery,” NASA CP 2133, Proceedings of a Workshop on Rotordynamic Instability Problems in High Performance Turbomachinery, Texas A&M University, pp. 3–14.
8.
Forte, P., and Latini, F., 1998, “Theoretical Rotordynamic Coefficients of Labyrinth Gas Seals: A Parameter Study on A Bulk Model,” Proceedings of the ISROMAC-7, International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, Feb., Honolulu, Hawaii, pp. 861–870.
9.
Greathead, S., and Bestow, P., 1976, “Investigations into Load Dependent Vibrations of the High Pressure Rotor on Large Turbo-Generators,” Proceedings of the 1st International Conference on Vibrations in Rotating Machinery (ImechE), Cambridge, England, pp. 279–286.
10.
Iwatsubo, T., 1980, “Evaluation of Instability Forces of Labyrinth Seals in Turbines or Compressors,” Proceedings of a Workshop on Rotordynamic Instability Problems in High-Performance Turbomachinery, Texas A&M University, NASA 2133, pp. 139–167.
11.
Launder
B. E.
Leschziner
M.
1978
, “Flow in Finite-Width, Thrust Bearings Including Inertial Effects, I-Laminar Flow, II-Turbulent Flow
,” ASME JOURNAL OF LUBRICATION TECHNOLOGY
, Vol. 100
, pp. 330
–345
.12.
Li, J., and Vance, J. M., 1995, “Effects of Clearance and Clearance Ratio on Two and Three Bladed TAMSEALs,” TRC-Seal-4-95, Turbomachinery Laboratory Research Progress Report, Texas A&M University, College Station, TX.
13.
Li, J., San Andre´s, L., and Vance, J. M., 1998, “A Bulk-Flow Analysis of Multiple-Pocket Gas Damper Seals,” ASME Paper 98-GT-013.
14.
Ransom, D. L., 1997, “Identification of Dynamic Force Coefficients of a labyrinth and Gas Damper Seal Using Impact Load Excitations,” Master’s thesis, Texas A&M University, College Station, TX.
15.
Ransom, D., Li, J., San Andre´s, L., and Vance, J. M., 1998, “Experimental Force Coefficients for a Two-Bladed Labyrinth Seal and a Four-Pocket Damper Seal,” accepted for publication at ASME JOURNAL OF TRIBOLOGY.
16.
Richards, R. L., Vance, J. M., and Zeidan, F. Y., 1995, “Using A Damper Seal to Eliminate Subsynchronous Vibrations in Three Back-to-Back Compressors,” Proceedings of 24th Turbomachinery Symposium, Houston, Sept., pp. 59–71.
17.
Scharrer
J. K.
1988
, “Theory Versus Experiment for the Rotordynamic Coefficient of Labyrinth Gas Seals: Part I—A Two Control Volume Model
,” ASME Journal of Vibration, Acoustics, Stress, and Reliability in Design
, Vol. 110
, pp. 270
–280
.18.
Vance, J. M., and Schultz, R. R., 1993, “A New Damper Seal for Turbomachinery,” Vibration of Rotating Systems, ASME Publication, DE-Vol. 60.
19.
Vance
J. M.
Li
J.
1996
, “Test Results of a New Damper Seal for Vibration Reduction in Turbomachinery
,” ASME Journal of Engineering for Gas Turbines and Power
, Vol. 118
, pp. 843
–846
.20.
Vance
J. M.
Cardon
B. P.
San Andre´s
L. A.
Storace
A. F.
1993
, “A Gas-Operated Bearing Damper for Turbomachinery
,” ASME Journal of Engineering for Gas Turbines and Power
, Vol. 115
, pp. 383
–389
.21.
Von Pragenau, G. L., 1982, “Damping Seals for Turbomachinery,” NASA Technical Paper 1987.
22.
Wyssmann, H. R., Pham, T. C., and Jenny, R. J., 1984, “Prediction of Stiffness and Damping Coefficients for Centrifugal Compressor Labyrinth Seals,” ASME Paper #84–GT–86.
23.
Yu, Z., and Childs, D. W., 1997, “A Comparison of Experimental Rotordynamic Coefficients and Leakage Characteristics Between Hole-Pattern Gas Damper Seals and A Honeycomb Seal,” ASME Paper 97–GT–9.
24.
Zeidan, F. Y., Perez, R. X., and Stephenson, E. M., 1993, “The Use of Honeycomb Seals in Stabilizing Two Centrifugal Compressors,” Proceedings of the 22nd Turbomachinery Symposium, Dallas, Sept., pp. 3–15.
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