0
Research Papers: Gas Turbines: Structures and Dynamics

Experimental Analysis of Floating Ring Annular Seals and Comparisons With Theoretical Predictions

[+] Author and Article Information
Antoine Mariot

CNES/PPRIME Institute,
CNRS, ENSMA ISAE,
University of Poitiers,
Chasseneuil Futuroscope 86962, France

Mihai Arghir

PPRIME Institute,
CNRS, ENSMA ISAE,
University of Poitiers,
Chasseneuil Futuroscope 86962, France

Pierre Hélies

Space Engines Division,
SNECMA,
Vernon 27208, France

Jérôme Dehouve

Direction des Lanceurs,
CNES,
Paris 75612, France

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received July 20, 2015; final manuscript received August 7, 2015; published online October 13, 2015. Editor: David Wisler.

J. Eng. Gas Turbines Power 138(4), 042503 (Oct 13, 2015) (9 pages) Paper No: GTP-15-1347; doi: 10.1115/1.4031347 History: Received July 20, 2015; Revised August 07, 2015

Floating ring annular seals represent one of the solutions for controlling leakage in high-speed rotating machinery. They are generally made of a carbon ring mounted in a steel ring for preserving their integrity. Low leakage is ensured by the small clearance of the annular space between the carbon ring and the rotor. Under normal operating conditions, the ring must be able to “float” on the rotor in order to accommodate its vibration. Impacts between the carbon ring and the rotor may occur when the annular seal is locked up against the stator and the amplitude of rotor vibrations are larger than the radial clearance. This situation is prohibited because it rapidly leads to the destruction of the carbon ring. The present work presents experimental results obtained for floating ring annular seals of 38 mm, tandem mounted in a buffer seal arrangement. The rotation speed was comprised of between 50 Hz and 350 Hz, and maximum pressure drop was 7 bar. For these operating conditions, the floating ring follows the rotor vibrations without any impacts. Comparisons were made with a theoretical model based on the equations of motion of the floating ring driven by mass inertia forces, hydrostatic forces in the (main) annular seal, and by friction forces on its radial face (also named the “nose” of the seal). The friction coefficient on the nose of the floating ring was estimated from Greenwood and Williamson's model for mixed lubrication. The present analysis validates the theoretical model used for predicting the dynamic response of the floating ring for a given rotor motion.

Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.

References

Booser, E. R. , 1983, Handbook of Lubrication, Volume II: Theory and Design, CRC Press, Boca Raton, FL.
Flitney, R. , 2007, Seal and Sealing Handbook, 5th ed., Elsevier, Oxford, UK.
Kirk, R. G. , and Miller, W. H. , 1979, “ The Influence of High Pressure Oil Seals on Turbo-Rotor Stability,” ASLE Trans., 22(1), pp. 14–24. [CrossRef]
Kirk, R. G. , 1988, “ Transient Response of Floating Ring Liquid Seals,” ASME J. Tribol., 110(3), pp. 572–577. [CrossRef]
Kirk, R. G. , and Brown, D. B. , 1990, “ Experimental Evaluation of Holding Forces in Floating Ring Seals,” IFToMM 3rd International Conference on Rotordynamics, Lyon, France, Sept. 9–12, pp. 319–323.
Semanate, J. , and San Andrés, L. , 1993, “ Analysis of Multi-Land High Pressure Oil Seals,” STLE Tribol. Trans., 36(4), pp. 661–669. [CrossRef]
Semanate, J. , and San Andrés, L. , 1993, “ A Quasi-Static Method for the Calculation of Lock-Up Speed in Floating Ring Oil Seals,” 4th Congreso de Turbo-Maquinaria, Querrettara, Mexico, Dec. 1–3, pp. 55–62.
Semanate, J. , and San Andrés, L. , 1994, “ Thermal Analysis of Locked Multi-Ring Oil Seals,” Tribol. Int., 27(3), pp. 197–206. [CrossRef]
Baheti, S. , and Kirk, R. G. , 1994, “ Thermo-Hydrodynamic Solution of Floating Ring Seals for High Pressure Compressors Using the Finite Element Method,” STLE Tribol. Trans., 37(2), pp. 336–346. [CrossRef]
Baheti, S. , and Kirk, R. G. , 1995, “ Finite Element Thermo-Hydrodynamic Solution of a Circumferentially Grooved Floating Oil Ring Seal,” STLE Tribol. Trans., 38(1), pp. 86–96. [CrossRef]
Baheti, S. , and Kirk, R. G. , 1996, “ Evaluation of Floating Ring Seals for Centrifugal Compressors Using the Finite Element Method,” ASME J. Vib. Acoust., 121(1), pp. 121–126.
Baheti, S. , and Kirk, R. G. , 1999, “ Analysis of High Pressure Liquid Seal Ring Distorsion and Stability Using Finite Element Methods,” ASME J. Tribol., 121(4), pp. 921–925. [CrossRef]
Suzuki, M. , Nosaka, M. , Kamijo, K. , and Kikuchi, M. , 1986, “ Research and Development of a Rotating Shaft Seal for a Liquid Hydrogen Turbopump,” Lubr. Eng., 42(3), pp. 162–169.
Oike, M. , Nosaka, M. , Kamijo, K. , Kikuchi, M. , and Watanabe, Y. , 1987, “ Experimental Study on High Pressure Gas Seals for a Liquid Oxygen Turbopump,” STLE Tribol. Trans. 31(1), pp. 91–97. [CrossRef]
Ha, T. W. , Lee, Y. B. , and Kim, C. H. , 2002, “ Leakage and Rotordynamic Analysis of a High Pressure Floating Ring Seal in the Turbo Pump Unit of a Liquid Rocket Engine,” Tribol. Int., 35(3), pp. 153–161. [CrossRef]
Lee, Y. B. , Shim, S. K. , Ryu, K. , and Kim, C. H. , 2005, “ Test Results for Leakage and Rotordynamic Coefficients of Floating Ring Seals in High-Pressure, High-Speed Turbopump,” STLE Tribol. Trans., 48(3), pp. 273–282. [CrossRef]
Lee, Y. B. , Kim, K. W. , Ryu, S. J. , and Jyung, J. T. , 2014, “ Leakage Performance and Rotordynamic Characteristics of Bump Floating Ring Seals for Turbopump,” ASME Paper No. GT2014-26274.
Emerick, M. , 1982, “ Vibration and Destabilizing Effects of Floating Ring Seals,” Rotordynamic Instability Problems in High Performance Turbomachinery—1982, Report No. NASA CP2133.
Artiles, A. W. , Shapiro, W. , and Jones, H. F. , 1984, “ Design Analysis of Rayleigh Step Floating Ring Seals,” ASLE Trans., 27(4), pp. 321–331. [CrossRef]
Hamm, R. , and Shapiro, W. , 1987, “ Testing of Helium-Buffered, Rayleigh Step Floating Ring Seals,” Lubr. Eng., 43(5), pp. 376–383.
Shapiro, W. , and Lee, C. C. , 1989, “ Advanced Helium Purge Seals for Liquid Oxygen (LOX) Turbopumps,” NASA Lewis Research Center, Cleveland, OH, Report No. NASA CR-182105.
Shapiro, W. , 2005, Users' Manual for Computer Code DYSEAL—Dynamic Response of Seals, Report No. NASA CR-2003-212368.
Nguyen, M.-H. , 2011, “ Analyse des Etanchéités Annulaires à Bague Flottante,” Ph.D. thesis, University of Poitiers, Poitiers, France.
Arghir, M. , Nguyen, M.-H. , Tonon, D. , and Dehouve, J. , 2012, “ Analytic Modeling of Floating Ring Annular Seals,” ASME J. Eng. Gas Turbines Power 134(5), p. 052507. [CrossRef]
Arghir, M. , and Nguyen, M.-H. , 2014, “ Non-Linear Analysis of Floating Ring Annular Seals: Stability and Impacts,” 9th IFToMM International Conference on Rotor Dynamics, Milano, Italy, Sept. 22–25, pp. 2007–2018, Springer, Cham, Switzerland.
Greenwood, J. A. , and Williamson, J. B. P. , 1966, “ Contact of Nominally Flat Surfaces,” Proc. R. Soc. London A, 295(1442), pp. 300–319. [CrossRef]
Lebeck, A. O. , 1991, Principles and Design of Mechanical Seals, Wiley, New York.
Petrov, E. P. , and Ewins, D. J. , 2004, “ Generic Friction Models for Time-Domain Variation Analysis of Bladed Disks,” ASME J. Turbomach., 126(1), pp. 184–192. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Simplified model of a floating ring seal

Grahic Jump Location
Fig. 2

Forces acting on the nose of the floating ring

Grahic Jump Location
Fig. 3

Ensemble view of the test rig

Grahic Jump Location
Fig. 4

Buffer seal arrangement

Grahic Jump Location
Fig. 5

Buffer seal support mounted on the test rig

Grahic Jump Location
Fig. 6

Theoretical eigenmodes of the rotor guided by the hydrostatic Lomakin bearings (KLomakin=3.5×107 N/m, zero damping)

Grahic Jump Location
Fig. 7

Metrology (left) and spectral analysis (right) of the test section of the rotor

Grahic Jump Location
Fig. 8

Trajectories of the rotor left section (a), of the floating rings 1–4 ((b)–(e)), and of the rotor right section (f) for Ω = 150 Hz and Psupply = 2 bar, no additional unbalance

Grahic Jump Location
Fig. 9

Trajectories of the rotor left section (a), of the floating rings 1–4 ((b)–(e)), and of the rotor right section (f) for Ω = 350 Hz and Psupply = 11 bar, 25 g mm unbalance

Grahic Jump Location
Fig. 10

Typical trajectories of the rotor (top) and of the floating ring (bottom) and their spectral content for Ω = 350 Hz and Psupply = 11 bar, 25 g mm unbalance

Grahic Jump Location
Fig. 11

Variation of the equivalent friction coefficient

Grahic Jump Location
Fig. 12

Measured and corrected trajectory of the rotor for Ω = 350 Hz and Psupply = 0.5 bar, no additional unbalance

Grahic Jump Location
Fig. 13

Trajectories of the floating ring, Ω = 250 Hz and small rotor amplitudes

Grahic Jump Location
Fig. 14

Trajectories of the floating ring, Ω = 350 Hz and large rotor amplitudes

Grahic Jump Location
Fig. 15

Experimental and theoretical synchronous amplitudes of the floating ring

Grahic Jump Location
Fig. 16

Relative position of the rotor and of the floating ring

Grahic Jump Location
Fig. 17

Minimum film thickness and phase angle between the rotor and the floating ring

Tables

Errata

Discussions

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