Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models—Part II: Physical Interpretation

  1. Corral, Roque 12
  2. Vega, Almudena 2
  1. 1 Advanced Engineering Direction, Industria de Turbopropulsores S.A.U., Madrid
  2. 2 Universidad Politécnica de Madrid
    info

    Universidad Politécnica de Madrid

    Madrid, España

    ROR https://ror.org/03n6nwv02

Zeitschrift:
Journal of Turbomachinery

ISSN: 0889-504X,  1528-8900

Datum der Publikation: 2018

Ausgabe: 140

Nummer: 12

Art: Artikel

DOI: 10.1115/1.4041377 GOOGLE SCHOLAR lock_openOpen Access editor

Andere Publikationen in: Journal of Turbomachinery

Ziele für nachhaltige Entwicklung

Zusammenfassung

The dimensionless model presented in part I of the corresponding paper to describe the flutter onset of two-fin rotating seals is exploited to extract valuable engineering trends with the design parameters. The analytical expression for the nondimensional work-per-cycle depends on three dimensionless parameters of which two of them are new. These parameters are simple but interrelate the effect of the pressure ratio, the height, and length of the interfin geometry, the seal clearance, the nodal diameter (ND), the fluid swirl velocity, the vibration frequency, and the torsion center location in a compact and intricate manner. It is shown that nonrelated physical parameters can actually have an equivalent impact on seal stability. It is concluded that the pressure ratio can be stabilizing or destabilizing depending on the case, whereas the swirl of the flow is always destabilizing. Finally, a simple method to extend the model to multiple interfin cavities, neglecting the unsteady interaction among them, is described.

Bibliographische Referenzen

  • 1. Mare, L. D., Imregun, M., Green, J., and Sayma, A. I., 2010, “A Numerical Study on Labyrinth Seal Flutter,” ASME J. Tribol., 132(2), p. 022201.
  • 2. Lewis, D., Platt, C., and Smith, E., 1979, “Aeroelastic Instability in F100 Labyrinth Air Seals,” AIAA J. Aircr., 16(7), pp. 484–490.
  • 3. Waschka, W., Witting, S., and Kim, S., 1992, “Influence of High Rotational Speeds on the Heat Transfer and Discharge Coefficients in Labyrinth Seals,” ASME J. Turbomach., 114(2), pp. 462–468.
  • 4. Willenborg, K., Kim, S., and Witting, S., 2001, “Effect of Reynolds Number and Pressure Ratio on Leakage Flow and Heat Transfer in a Stepped Labyrinth Seal,” ASME J. Turbomach., 123(4), pp. 815–822.
  • 5. Alford, J., 1964, “Protection of Labyrinth Seals From Flexural Vibration,” ASME J. Eng. Gas Turbines Power, 86(2), pp. 141–147.
  • 6. Ehrich, F., 1968, “Aeroelastic Instability in Labyrinth Seals,” ASME J. Eng. Gas Turbines Power, 90(4), pp. 369–374.
  • 7. Alford, J. S., 1975, “Nature, Causes and Prevention of Labyrinth Air Seal Failures,” AIAA J. Aircr., 12(4), pp. 313–318.
  • 8. Abbot, D. R., 1981, “Advances in Labyrinth Seal Aeroelastic Instability Prediction and Prevention,” ASME J. Eng. Gas Turbines Power, 103(2), pp. 308–312.
  • 9. Corral, R., and Vega, A., 2016, “The Low Reduced Frequency Limit of Vibrating Airfoils—Part I: Theoretical Analysis,” ASME J. Turbomach., 138(2), p. 021004.
  • 10. Corral, R., and Vega, A., 2016, “Physics of Vibrating Turbine Airfoils at Low Reduced Frequency,” AIAA J. Propul. Power, 32(2), pp. 325–336.
  • 11. Barbarossa, F., Parry, A. B., Green, J. S., and di Mare, L., 2016, “An Aerodynamic Parameter for Low-Pressure Turbine Flutter,” ASME J. Turbomach., 138(5), p. 051001.
  • 12. Corral, R., and Vega, A., 2017, “Quantification of the Influence of Unsteady Aerodynamic Loading on the Damping Characteristics of Oscillating Airfoils at Low Reduced Frequency—Part I: Theoretical Support,” ASME J. Turbomach., 139(3), p. 0310009.
  • 13. Phibel, R., and Mare, L. D., 2011, “Comparison Between a CFD Code and a Three-Control-Volume Model for Labyrinth Seal Flutter Predictions,” ASME Paper No. GT2011-46281.
  • 14. Vega, A., and Corral, R., 2016, “The Low Reduced Frequency Limit of Vibrating Airfoils—Part II: Numerical Experiments,” ASME J. Turbomach., 128(2), p. 021005.
  • 15. Vega, A., and Corral, R., 2017, “Quantification of the Influence of Unsteady Aerodynamic Loading on the Damping Characteristics of Oscillating Airfoils at Low Reduced Frequency. Part ii: Numerical Verification,” ASME J. Turbomach., 139(3), p. 031010.
  • 16. Corral, R., and Vega, A., 2018, “Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models—Part I: Theoretical Support,” ASME J. Turbomach. (accepted).
  • 17. Phibel, R., Mare, L. D., and Imregun, J. G. M., 2009, “Labyrinth Seal Aeroelastic Stability, a Numerical Investigation,” 12th International Symposium on Unsteady Aerodynamics, Aeroacoustics & Aeroelasticity of Turbomachines, London, Sept. 1–4, Paper No. I12-S2-3.