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Research Papers: Gas Turbines: Turbomachinery

Exploitation of Acoustic Effects in Film Cooling

[+] Author and Article Information
Matthew Collins

Osney Thermofluids Laboratory,
Department of Engineering Science,
University of Oxford,
Parks Road,
Oxford OX1 3PJ, UK
e-mail: matthew.collins@eng.ox.ac.uk

Thomas Povey

Osney Thermofluids Laboratory,
Department of Engineering Science,
University of Oxford,
Parks Road,
Oxford OX1 3PJ, UK
e-mail: thomas.povey@eng.ox.ac.uk

Contributed by the Turbomachinery Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received March 3, 2015; final manuscript received March 14, 2015; published online April 8, 2015. Editor: David Wisler.

J. Eng. Gas Turbines Power 137(10), 102602 (Oct 01, 2015) (9 pages) Paper No: GTP-15-1077; doi: 10.1115/1.4030102 History: Received March 03, 2015; Revised March 14, 2015; Online April 08, 2015

There have been numerous studies of the behavior of shaped film cooling holes for turbine applications. It is known that the introduction of coolant is an unsteady process, and a handful of studies have described and characterized the unsteadiness. To the best of our knowledge, there are no studies in which unsteady acoustic effects have been actively exploited such that they have led to novel designs with improved cooling performance. This paper discusses the fundamental mechanism of pressure wave propagation through cooling holes and describes systems in which holes which have been acoustically shaped have led to a direct improvement in film cooling hole performance. The mechanism relies on sequential pressure wave reflection within an acoustically shaped hole and is therefore applicable in regions where the external surface is subject to large pressure wave fluctuations at high frequency. The principle is developed analytically, and then demonstrated with a number of computational fluid dynamics (CFD) simulations. We demonstrate that a desired temporal mass flow rate profile can be achieved by appropriate acoustic shaping of the cooling hole. The purpose of this paper is to describe the fundamental design considerations relevant to acoustic shaping. The discussion is developed with reference to a film cooling system for the over-tip region of an unshrouded rotor. The performance benefit of the system in terms of modulation of unsteady mass flux and ingestion characteristics is quantified. It is believed that this is the first time this significant effect has been exploited in film cooling design.

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References

Winterbone, D. E., and Pearson, R. J., 2000, Theory of Engine Manifold Design: Wave Action Methods for IC Engines, Professional Engineering Publishers, London.
Chana, K. S., and Haller, B., 2009, “Novel Turbine Rotor Shroud Film-Cooling Design and Validation, Part 1,” ASME Paper No. GT2009-60242. [CrossRef]
Lowe, C. C., Powis, A. C., and Clarke, J. P., 2003, “Turbine Shroud Asymmetrical Cooling Elements,” U.S. Patent No. US7147432.
Chana, K. S., and Haller, B., 2009, “Novel Turbine Rotor Shroud Film-Cooling Design and Validation, Part 2,” ASME Paper No. GT2009-60246. [CrossRef]
El-Gabry, L. A., and Ameri, A. A., 2011, “Comparison of Steady and Unsteady RANS Heat Transfer Simulations of Hub and Endwall of a Turbine Blade Passage,” ASME J. Turbomach., 133(3), p. 031010. [CrossRef]
Chana, K. S., and Jones, T. V., 2002, “An Investigation on Turbine Tip and Shroud Heat Transfer,” ASME Paper No. GT2002-30554. [CrossRef]
Thorpe, S. J., Yoshino, S., Ainsworth, R. W., and Harvey, N. W., 2004, “An Investigation of the Heat Transfer and Static Pressure on the Over-Tip Casing Wall of an Axial Turbine Operating at Engine Representative Flow Conditions. (II). Time-Resolved Results,” Int. J. Heat Fluid Flow, 25(6), pp. 945–960. [CrossRef]
Thorpe, S. J., Miller, R. J., Yoshino, S., Ainsworth, R. W., and Harvey, N. W., 2007, “The Effect of Work Processes on the Casing Heat Transfer of a Transonic Turbine,” ASME J. Turbomach., 129(1), pp. 84–91. [CrossRef]
Behr, T., Kalfas, A. I., and Abhari, R. S., 2007, “Unsteady Flow Physics and Performance of a One-and-1/2-Stage Unshrouded High Work Turbine,” ASME J. Turbomach., 129(2), pp. 348–359. [CrossRef]
Kentfield, J. A. C., 1993, Nonsteady, One-Dimensional, Internal, Compressible Flows, Oxford University Press, Oxford, UK.
Courant, R., and Friedrichs, K. O., 1948, Supersonic Flow and Shock Waves, Interscience Publishers, New York.
Anderson, J. D., 2004, Modern Compressible Flow: With Historical Perspective, McGraw-Hill, Boston.
Hilditch, M. A., Fowler, A., Jones, T. V., Chana, K. S., Oldfield, M. L. G., Ainsworth, R. W., Hogg, S. I., Anderson, S. J., and Smith, G. C., 1994, “Installation of a Turbine Stage in the Pyestock Isentropic Light Piston Facility,” ASME Paper No. 94-GT-277. [CrossRef]
Qureshi, I., Beretta, A., Chana, K., and Povey, T., 2011, “Effect of Aggressive Inlet Swirl on Heat Transfer and Aerodynamics in an Unshrouded Transonic HP Turbine,” ASME Paper No. GT2011-46038. [CrossRef]
Chana, K., Cardwell, D., and Jones, T., 2013, “A Review of the Oxford Turbine Research Facility,” ASME Paper No. GT2013-95687. [CrossRef]

Figures

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Fig. 1

HP rotor casing film cooled segments [3]

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Fig. 2

Propagation of an infinitesimally weak compression wave along a duct of uniform area

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Fig. 3

Summary of Riemann invariant equations governing pressure wave propagation

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Fig. 4

Steepening of a compression wave (left) and fanning of an expansion wave (right)

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Fig. 5

Pressure wave interactions with a closed end (left) and an open end (right)

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Fig. 6

Structured mesh of a typical 2D axisymmetric hole

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Fig. 7

Unsteady outlet temporal pressure profile pm(t)

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Fig. 8

Plot of unsteady p within cylindrical hole. L1 = 0.25λ, p0c/pm¯ = 1.25.

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Fig. 9

Plot of unsteady M within cylindrical hole. L1 = 0.25λ, p0c/pm¯ = 1.25.

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Fig. 10

Plot of unsteady p within cylindrical hole. L1 = 0.055λ, p0c/pm¯ = 1.25.

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Fig. 11

Plot of unsteady M within cylindrical hole. L1 = 0.055λ, p0c/pm¯ = 1.25.

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Fig. 12

Compound hole geometry and mesh

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Fig. 13

Plot of unsteady p within compound cylindrical hole. L1 = 0.17λ, L2 = 0.055λ, p0c/pm¯ = 1.25.

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Fig. 14

Plot of unsteady M within compound cylindrical hole. L1 = 0.17λ, L2 = 0.055λ, p0c/pm¯ = 1.25.

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Fig. 15

Plot of m·m across exit plane of holes. p0c/pm¯ = 1.25.

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Fig. 16

Plot of minimum pressure ratio for ingestion and normalized standard deviation of m·m across exit plane of cylindrical holes of different lengths

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