Abstract
Film cooling is an important measure to enable an increase of the inlet temperature of a gas turbine and, thereby, to improve its overall efficiency. The coolant is ejected through spanwise rows of holes in the blades or endwalls to build up a film shielding the material. The holes often are inclined in the downstream direction and give rise to a kidney vortex. This is a counter-rotating vortex pair, with an upward flow direction between the two vortices, which tends to lift off the surface and to locally feed hot air towards the blade outside the pair. Reversing the rotational sense of the vortices reverses these two drawbacks into advantages. In the considered case, an anti-kidney vortex is generated using two subsequent rows of holes both inclined downstream and yawed spanwise with alternating angles. In a previous study, we performed large-eddy simulations (which focused on the fully turbulent boundary layer) of this anti-kidney vortex film-cooling and compared them to a corresponding physical experiment. The present work analyzes the simulated flow field in detail, beginning in the plenum (inside the blade or endwall) through the holes up to the mixture with the hot boundary layer. To identify the vortical structures found in the mean flow and in the instantaneous flow, we mostly use the λ 2 criterion and the line integral convolution (LIC) technique indicating sectional streamlines. The flow regions (coolant plenum, holes, and boundary layer) are studied subsequently and linked to each other. To track the anti-kidney vortex throughout the boundary layer, we propose two criteria which are based on vorticity and on LIC results. This enables us to associate the jet vortices with the cooling effectiveness at the wall, which is the key feature of film cooling.
Similar content being viewed by others
References
Goldstein R. J.: Film Cooling, In: Advances in Heat Transfer, vol.7, pp.321–379, (1971).
Cortelezzi L., Karagozian A. R.: On the Formation of the Counter-Rotating Vortex Pair in Transverse Jets, Journal of Fluid Mechanics, vol.446, pp.347–373, (2001).
Fric T. F., Roshko A.: Vortical Structure in the Wake of a Transverse Jet, Journal of Fluid Mechanics, vol.279, pp.1–47, (1994).
Bagheri S., Schlatter P., Schmid P. J., Henningson D. S.: Global Stability of a Jet in Crossflow, Journal of Fluid Mechanics, vol.624, pp.33–44, (2009).
Lee S. W., Kim Y. B., Lee J. S.: Flow Characteristics and Aerodynamic Losses of Film Cooling Jets with Compound Angle Orientations, Journal of Turbomachinery, vol.119, pp.310–319, (1997).
Haven B. A., Kurosaka M.: Kidney and Anti-Kidney Vortices in Crossflow Jets, Journal of Fluid Mechanics, vol.352, pp.27–64, (1997).
Jubran B. A., Maiteh B. Y.: Film Cooling and Heat Transfer from a Combination of Two Rows of Simple and/or Compound Angle Holes in Inline and/or Staggered Configuration, International Journal of Heat and Mass Transfer, vol.34, Num 6, pp.495–502, (1999).
Farhadi-Azar R., Ramezanizadeh M., Taeibi-Rahni M., Salimi M.: Compound Triple Jets Film Cooling Improvements via Velocity and Density Ratios: Large Eddy Simulation, Journal of Fluids Engineering, vol.133, Num 3, pp.031202-1–13, (2011).
Yao Y., Maidi M.: Direct Numerical Simulation of Single and Multiple Square Jets in Cross-Flow, Journal of Fluids Engineering, vol.133, Num 3, pp.031201-1–10, (2011).
Dhungel A., Lu Y., Phillips W, Ekkad S. V., Heidmann J.: Film Cooling From a Row of Holes Supplemented with Antivortex Holes, Journal of Turbomachinery, vol. 131, Num 2, pp.021007-1–10, (2009).
Ahn J., Jung I. S., Lee J. S.: Film Cooling from Two Rows of Holes with Opposite Orientation Angles: Injectant Behavior and Adiabatic Film Cooling Effectiveness, International Journal of Heat and Fluid Flow, vol.24, Num 1, pp.91–99, (2003).
Kusterer K., Bohn D., Sugimoto T., Tanaka R.: Dou ble-Jet Ejection of Cooling Air for Improved Film Cooling, Journal of Turbomachinery, vol.129, pp.809–815, (2007).
Gräf L., Kleiser L.: Large-Eddy Simulation of Double-Row Compound-Angle Film Cooling: Setup and Validation, Computers and Fluids, vol.43, pp.58–67, (2011).
Vos J. B., Van Kemenade V., Ytterström A., Rizzi A. W.: Parallel NSMB: An Industrialized Aerospace Code for Complete Aircraft Simulations, In: Parallel Computational Fluid Dynamics, North Holland, Amsterdam, 1996, pp.49–58, (1997).
Gräf L., Kleiser L.: Large-Eddy Simulation of Double-Row Compound-Angle Film-Cooling: Computational Aspects, In: High Performance Computing on Vector Systems 2010, pp.185–196, Springer, Heidelberg, (2010).
Schlatter P., Stolz S., Kleiser L.: LES of Transitional Flows using the Approximate Deconvolution Model, International Journal of Heat and Fluid Flow, vol.25, Num. 3, pp.549–558, (2004).
Jarrin N., Benhamadouche S., Laurence D., Prosser R.: A Synthetic-Eddy-Method for Generating Inflow Conditions for Large-Eddy Simulations, International Journal of Heat and Fluid Flow, vol.27, Num 4, pp.585–593, (2006).
Pritz B., Magagnato F., Gabi M.: Inlet Condition for Large-Eddy Simulation Applied to a Combustion Chamber, In: Conference on Modelling Fluid Flow 06, pp.845–850, Budapest, (2006).
Thompson K. W.: Time Dependent Boundary Conditions for Hyperbolic Systems, II, Journal of Computational Physics, vol.89, pp.439–461, (1990).
Jeong J., Hussain F.: On the Identification of a Vortex, Journal of Fluid Mechanics, vol.285, pp.69–94, (1995).
Terzi von D. A., Sandberg R. D., Fasel H. F.: Identification of Large Coherent Structures in Supersonic Axisymmetric Wakes, Computers and Fluids, vol.38, Num 8, pp.1638–1650, (2009).
Cabral B., Leedom L.C.: Imaging Vector Fields Using Line Integral Convolution, In: Proceedings of the 20th Annual Conference on Computer Graphics and Interactive Techniques, pp.263–270, New York, (1993).
Truesdell C. A.: The Kinematics of Vorticity, Num 19 in Indiana University Publications Science Series, Indiana University Press, Bloomington, (1954).
Hunt J. C. R., Wray A. A., Moin P.: Eddies, Streams, and Convergence Zones in Turbulent Flows, In: Proceedings of the 1988 Summer Program, Stanford, pp.193–208, (1988).
Chong M. S., Perry A. E., Cantwell B. J.: A General Classification of Three-Dimensional Flow Fields, Physics of Fluids A: Fluid Dynamics, vol.2, Num 5, pp.765–777, (1990).
Wilcox D. C.: Basic Fluid Mechanics, DCW Industries, La Sañada, 2nd edition, (2000).
Ziefle J., Kleiser L.: Assessment of a Film-Cooling Flow Structure by Large-Eddy Simulation, Journal of Turbulence, vol.9, Num 29, pp.1–25, (2008).
Bogard D. G., Thole K. A.: Gas Turbine Film Cooling, Journal of Propulsion and Power, vol.22, Num 2, pp.249–270, (2006).
Yuan L. L., Street R. L.: Trajectory and Entrainment of a Round Jet in Crossflow, Physics of Fluids, vol.10, Num 9, pp.2323–2335, (1998).
Aga V., Rose M., Abhari R. S.: Experimental Flow Structure Investigation of Compound Angled Film Cooling, Journal of Turbomachinery, vol.130, Num 3, pp.031005-1–8, (2008).
Robinson S. K.: Coherent Motions in the Turbulent Boundary Layer, Annual Review in Fluid Mechanics, vol.23, pp.601–639, (1991).
Author information
Authors and Affiliations
Additional information
This work was partly funded by Swiss National Science Foundation (SNF) with project number 200020-116310.
Rights and permissions
About this article
Cite this article
Gräf, L., Kleiser, L. Flow-field analysis of anti-kidney vortex film cooling. J. Therm. Sci. 21, 66–76 (2012). https://doi.org/10.1007/s11630-012-0520-y
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11630-012-0520-y