Flow, Turbulence and Combustion

, Volume 88, Issue 1–2, pp 101–120 | Cite as

Turbulent Heat Transfer and Large Coherent Structures in Trailing-edge Cutback Film Cooling

  • Hayder Schneider
  • Dominic von Terzi
  • Hans-Jörg Bauer
Article

Abstract

Film cooling is a key technology for improving the thermal efficiency and power output of gas turbines. The trailing-edge section of high-pressure turbine blades can be efficiently cooled by ejecting a film over a cutback on the pressure side of the blade. In this paper, results of Large–Eddy Simulations (LES) are presented that match an existing experimental setup. Altogether, eight simulations with the blowing ratio M varying as the only parameter were performed over a range from M = 0.35 to 1.4. Reasonably good agreement between LES and experiments were obtained for flow field statistics and adiabatic film-cooling effectiveness ηaw. Within a limited range of blowing ratios, an increase in the blowing ratio results in a counter-intuitive decrease of the cooling effectiveness. The present work suggests a mechanism that can explain this behavior. The visualization and analysis of large coherent structures showed that there exists dominant clockwise-rotating structures that can give rise to a combined upstream- and wall-directed turbulent heat flux. This turbulent heat flux represents the main contribution of the total heat flux and causes a significantly intensified thermal mixing process, which in turn results in the counter-intuitive decrease of the cooling effectiveness.

Keywords

Large–Eddy simulation Large coherent structures Turbulent mixing Heat transfer Film cooling 

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References

  1. 1.
    Bunker, R.S.: Cooling design analysis. DOE–NETL, The Gas Turbine Handbook. http://www.netl.doe.gov/technologies/coalpower/turbines/refshelf/handbook/TableofContents. (2006). Accessed 30 August 2010
  2. 2.
    Holloway, D.S., Leylek, J.H., Buck, F.A.: Pressure Side Bleed Film Cooling: Part I–Steady Framework for Experimental and Computational Results. ASME Paper No. GT–2002–30471 (2002)Google Scholar
  3. 3.
    Holloway, D.S., Leylek, J.H., Buck, F.A.: Pressure Side Bleed Film Cooling: Part II–Steady Framework for Experimental and Computational Results. ASME Paper No. GT–2002–30472 (2002)Google Scholar
  4. 4.
    Medic, G., Durbin, P.A.: Unsteady effects on trailing edge cooling. J. Heat Transfer 127, 388–392 (2005)CrossRefGoogle Scholar
  5. 5.
    Joo, J., Durbin, P.A.: Simulation of turbine blade trailing edge cooling. ASME J. Fluids Eng. 131 (2009). doi:10.1115/1.3054287 Google Scholar
  6. 6.
    Martini, P., Schulz, A., Bauer, H.-J., Whitney, C.F.: Detached Eddy simulation of film cooling performance on the trailing edge cutback of gas turbine airfoils. ASME J. Turbomach. 128, 292–300 (2006)CrossRefGoogle Scholar
  7. 7.
    Pope, S.B.: Turbulent Flows. Cambridge University Press, Cambridge (2000)MATHGoogle Scholar
  8. 8.
    Fröhlich, J., von Terzi, D.A.: Hybrid LES/RANS methods for the simulation of turbulent flows. Prog. Aerosp. Sci. 44, 349–377 (2008)CrossRefGoogle Scholar
  9. 9.
    Martini, P., Schulz, A., Bauer, H.-J.: Film cooling effectiveness and heat transfer on the trailing edge cutback of gas turbine airfoils with various internal cooling designs. ASME J. Turbomach. 128, 196–206 (2006)CrossRefGoogle Scholar
  10. 10.
    Martini, P.: Filmkühlung hoch-beanspruchter Turbinen-schaufel-hinter-kanten: Wärme-übergang und Strömung im Nahfeld praxis-bezogener Ausblase-spalte. Dissertation, University of Karls-ruhe, Karlsruhe, Germany (2008)Google Scholar
  11. 11.
    Horbach, T., Schulz, A., Bauer, H.-J.: Trailing edge film cooling of gas turbine airfoils—external cooling performance of various internal pin fin configurations. ASME J. Turbomach. 133 (2011). doi:10.1115/1.4002964 Google Scholar
  12. 12.
    Schneider, H., von Terzi, D.A., Bauer, H.-J.: Large–Eddy simulations of trailing-edge cutback film cooling at low blowing ratio. Int. J. Heat Fluid Flow 31, 767–775 (2010). doi:10.1016/j.ijheatfluidflow.2010.06.010 CrossRefGoogle Scholar
  13. 13.
    Hinterberger, C.: Dreidimensionale und tiefengemittelte Large–Eddy-Simulation von Flachwasser-strömungen. Dissertation, University of Karls-ruhe, Karlsruhe, Germany (2004)Google Scholar
  14. 14.
    Lund,T.S., Wu, X., Squires, K.D.: Generation of turbulent inflow data for spatially-developing boundary layer simulations. J. Comput. Phys. 140, 233–258 (1998)MathSciNetMATHCrossRefGoogle Scholar
  15. 15.
    von Terzi, D.A., Sandberg, R.D., Fasel, H.F.: Identification of large coherent structures in supersonic axisymmetric wakes. Comput. Fluids 38, 1638–1650 (2009)MathSciNetCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • Hayder Schneider
    • 1
  • Dominic von Terzi
    • 1
  • Hans-Jörg Bauer
    • 1
  1. 1.Institut für Thermische StrömungsmaschinenKarlsruhe Institute of Technology (KIT)KarlsruheGermany

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