Higher Order Conceptual Model for Labyrinth Seal Flutter

  1. Greco, Michele 1
  2. Vega, Almudena 1
  3. Corral, Roque 12
  1. 1 Universidad Politécnica de Madrid
    info

    Universidad Politécnica de Madrid

    Madrid, España

    ROR https://ror.org/03n6nwv02

  2. 2 Advanced Engineering Direction, Industria de Turbopropulsores S.A.U., 28108 Madrid, Spain
Revista:
Journal of Turbomachinery

ISSN: 0889-504X,  1528-8900

Año de publicación: 2021

Volumen: 143

Número: 7

Tipo: Artículo

DOI: 10.1115/1.4050334 GOOGLE SCHOLAR lock_openAcceso abierto editor

Otras publicaciones en: Journal of Turbomachinery

Resumen

A simple nondimensional model to describe the flutter onset of two-fin straight labyrinth seals (Corral, R., and Vega, A., 2018, “Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models. Part I: Theoretical Background,” ASME J. Turbomach., 140(10), p. 121006) is extended to account for nonisentropic flow perturbations. The isentropic relationship is replaced by the more general integral energy equation of the inter-fin cavity. A new expression for the Corral and Vega stability criterion is derived, which is very consistent with the previous model in the whole design space of the seal but for torsion centers located in the high-pressure side close to the seal. The new model formally depends on more dimensionless parameters since the existing parameter grouping of the previous model does not hold anymore, but this dependency is weak in relative terms. The model blends the limit where the discharge time of the inter-fin cavity is much longer than the vibration period, and the flow is nearly isentropic, and the opposite limit, where the perturbations are isothermic, gracefully. A few numerical examples obtained using a three-dimensional linearized frequency domain solver are included to support the model and show that the trends are correct, but the body of the numerical work will be presented in a separated article. The matching between the work-per-cycle obtained with the model and frequency domain solver is good. It is shown that some weird trends obtained using linearized unsteady simulations are qualitatively consistent with the current model but not with the previous one (Corral, R., and Vega, A., 2018, “Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models. Part I: Theoretical Background,” ASME J. Turbomach., 140(10), p. 121006). The largest differences between the new and the previous model are seen when the seal is supported at the high-pressure side.

Referencias bibliográficas

  • 1. Corral, R., and Vega, A., 2018, “Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models. Part I: Theoretical Background,” ASME J. Turbomach., 140(10), p. 121006. 10.1115/1.4041373
  • 2. Chupp, R., Hendricks, R., Lattime, S., and Steinetz, B., 2006, “Sealing in Turbomachinery,” AIAA J. Propulsion Power, 22(2), pp. 314-–349. 10.2514/1.17778
  • 3. Vahdati, M., Smith, N., and Zhao, F., 2015, “Influence of Intake on Fan Blade Flutter,” ASME J. Turbomach., 137(8), p. 081002. 10.1115/1.4029240
  • 4. 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. 10.1115/1.4031776
  • 5. Corral, R., Beloki, J., Calza, P., and Elliot, R., 2019, “Flutter Generation and Control Using Mistuning in a Turbine Rotating Rig,” AIAA J., 57(2), pp. 782–795. 10.2514/1.J056943
  • 6. Stapelfeldt, S., and Vahdati, M., 2019, “Improving the Flutter Margin of an Unstable Fan Blade,” ASME J. Turbomach., 141(7), p. 071006. 10.1115/1.4042645
  • 7. Alford, J. S., 1971, “Labyrinth Seal Designs Have Benefitted From Development and Service Experience,” SAE International, p. 710435. https://doi.org/10.4271/710435
  • 8. Alford, J. S., 1975, “Nature, Causes and Prevention of Labyrinth Air Seal Failures,” AIAA J. Aircraft, 12(4), pp. 313–318. 10.2514/3.44449
  • 9. Lewis, D., Platt, C., and Smith, E., 1979, “Aeroelastic Instability in F100 Labyrinth Air Seals,” AIAA J. Aircraft, 16(7), pp. 484–490. 10.2514/3.58552
  • 10. Vega, A., and Corral, R., 2018, “Conceptual Flutter Analysis of Labyrinth Seals Using Analytical Models. Part II: Physical Interpretation,” ASME J. Turbomach., 140(10), p. 121007. 10.1115/1.4041377
  • 11. Corral, R., Greco, M., and Vega, A., 2019, “Tip-Shroud Labyrinth Seal Impact on the Flutter Stability of Turbine Rotor Blades,” ASME J. Turbomach., 141(10), p. 101006. 10.1115/1.4043962
  • 12. Corral, R., Vega, A., and Greco, M., 2020, “Conceptual Flutter Analysis of Stepped Seals,” ASME J. Eng. Gas Turbines Power, 142(7), p. 071001. 10.1115/1.4046419
  • 13. Miura, T., and Sakai, N., 2019, “Numerical and Experimental Studies of Labyrinth Seal Aeroelstic Instability,” ASME J. Eng. Gas Turbines Power, 141(11), p. 111005. 10.1115/1.4044353
  • 14. Alford, J., 1964, “Protection of Labyrinth Seals From Flexural Vibration,” ASME J. Eng. Gas Turbines Power, 86(2), pp. 141–147. 10.1115/1.3677564
  • 15. Alford, J., 1967, “Protecting Turbomachinery From Unstable and Oscillatory Flows,” ASME J. Eng. Gas Turbines Power, 89(4), pp. 513–527. 10.1115/1.3616719
  • 16. Ehrich, F., 1968, “Aeroelastic Instability in Labyrinth Seals,” ASME J. Eng. Gas Turbines Power, 90(4), pp. 369–374. 10.1115/1.3609221
  • 17. Abbot, D. R., 1981, “Advances in Labyrinth Seal Aeroelastic Instability Prediction and Prevention,” ASME J. Eng. Gas Turbines Power, 103(2), pp. 308–312. 10.1115/1.3230721
  • 18. Zhuang, Q., 2012, “Parametric Study on the Aeroelastic Stability of Rotor Seals,” Master’s thesis, Royal Institute of Technology, Stockholm, Sweden.
  • 19. Hirano, T., Guo, Z., and Kirk, R. G., 2005, “Application of Computational Fluid Dynamics Analysis for Rotating Machinery-Part II: Labyrinth Seal Analysis,” ASME J. Eng. Gas Turbines Power, 127(4), pp. 820–826. 10.1115/1.1808426
  • 20. Mare, L. D., Imregun, M., Green, J., and Sayma, A. I., 2010, “A Numerical Study on Labyrinth Seal Flutter,” ASME J. Tribology, 132(2), pp. 022201–022207. 10.1115/1.3204774
  • 21. Corral, R., and Vega, A., 2016, “Physics of Vibrating Turbine Airfoils at Low Reduced Frequency,” AIAA J. Propulsion Power, 32(2), pp. 325–336. 10.2514/1.B35572
  • 22. 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. 10.1115/1.4034976
  • 23. 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. 10.1115/1.4031777
  • 24. 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. 10.1115/1.4034978
  • 25. Corral, R., Escribano, A., Gisbert, F., Serrano, A., and Vasco, C., 2003, “Validation of a Linear Multigrid Accelerated Unstructured Navier-Stokes Solver for the Computation of Turbine Blades on Hybrid Grids,” 9th AIAA/CEAS Aeroacoustics Conference, Hilton Head, SC, May 12–14, AIAA Paper No. 2003–3326.
  • 26. Burgos, M., and Chia, J., 2009, “Rapid Meshing of Turbomachinery Rows Using Semi-Unstructured Multi-Block Conformal Grids,” Eng. Comput., 26(4), pp. 351–363. 10.1007/s00366-009-0169-7