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Similarity analysis of model experiments for film cooling in gas turbines

Ähnlichkeitsanalyse zu Modellversuchen der Filmkühlung von Gasturbinen

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Abstract

This report investigates our present ability to predict the thermal performance of film cooling arrangements used to protect the hot components of gas turbines. The required information is usually obtained by model experiments carried out at near room temperature as opposed to the high temperature encountered in the gas turbines. Dimensional or similarity analysis is used to develope the functional relationships for film effectiveness and convective heat transfer and the use of mass transfer experiments with foreign gas injection and naphthalene sublimation based on the heat-mass transfer analogy is discussed. The law of superposition is used to describe the combined effects of film cooling, surface convection or radiation and frictional heating. An order of magnitude estimate indicates to what extent local temperature gradients are alleviated in the cooled walls by internal heat conduction.

Zusammenfassung

Die vorliegende Arbeit untersucht den gegenwärtigen Stand unserer Fähigkeit, die Wirksamkeit der Filmkühlung für Gasturbinen vorauszubestimmen. Die rechnerischen Unterlagen dazu werden meist durch Modellversuche bei mäßigen Temperaturen bestimmt, im Gegensatz zu den hohen Temperaturen in Gasturbinen. Ähnlichkeitsanalyse hilft dann zu ermitteln, inwieweit die durch Modellversuche erhaltenen Beziehungen auf den tatsächlichen Vorgang übertragbar sind. Die Analogie zwischen Wärme-und Stoffübergang eröffnet weitere Möglichkeiten für Modellversuche, und Superpositionsverfahren erlauben es, konvektiven Wärmeübergang und thermische Strahlung mit Filmkühlung zu kombinieren. Der Temperaturausgleich durch Wärmeleitung in der filmgekühlten Wand wird größenmäßig abgeschätzt.

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Abbreviations

c p :

specific heat

k :

thermal conductivity

M :

blowing parameter

p :

pressure

Pr :

Prandtl number

q :

heat flux per unit area

R :

gas constant

r :

recovery factor

Re :

Reynolds number

St :

Stanton number

T :

Temperature

t :

temperature difference

u, v, w :

velocity components

V :

Velocity

x, y, z :

coordinates

o :

upstream, at 300 K

f :

film cooling

l :

secondary fluid

aw :

adiabatic wall surface

H :

heat

i :

isoenergetic

M :

mass

w :

wall surface

α :

thermal diffusivity

αβγ :

exponents

ε :

turbulent diffusivity

η :

film effectiveness

ϱ :

density

ν :

kinematic viscosity

μ :

viscosity

References

  1. Nusselt, W.: Das Grundgesetz des Wärmeüberganges. Gesundheits-Ingenieur 38 (1915) 447–482, 490–496

    Google Scholar 

  2. Eckert, E. R. G.; Drake, R. M. Jr.: Heat and mass transfer. New York: McGraw-Hill (1950), pp. 229–239

    Google Scholar 

  3. Ito, S.; Goldstein, R. J.; Eckert, E. R. G.: Film cooling of a gas turbine blade. Eng. for Power 100 (1978) 476–481

    Google Scholar 

  4. Pedersen, D. R.; Eckert, E. R. G.; Goldstein, R. J.: Film cooling with large density differences between mainstream and the secondary fluid measured by the heat-mass transfer analogy. J. Heat Transfer 99 (1977) 620–627

    Google Scholar 

  5. Eckert, E. R. G.: Analogies to heat transfer processes. In: Eckert, E. R. G.: Measurements in Heat Transfer, 2nd edition. Washington: Hemisphere 1986

    Google Scholar 

  6. Shadid, J. N.; Eckert, E. R. G.: The mass transfer analogy to heat transfer in fluids with temperature-dependent properties. J. Turbomachinery 113 (1991) 27–33

    Google Scholar 

  7. Eckert, E. R. G.: Analysis of film cooling and full-coverage film cooling of gas turbine blades. J. Eng. for Power 106 (1984) 206–213

    Google Scholar 

  8. Goldstein, R. J.: Film cooling. In Irvine, T. F Jr.; Hartnett, J. P: Advances in Heat Transfer. New York: Academic Press (1971), pp. 327–329

    Google Scholar 

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Authors and Affiliations

  1. Mechanical Engineering Dept., University of Minnesota, 55455, Minneapolis, MN, USA

    E. R. G. Eckert

Authors
  1. E. R. G. Eckert
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Dedicated to Prof. Dr.-Ing. U. Grigull's 80th birthday

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Eckert, E.R.G. Similarity analysis of model experiments for film cooling in gas turbines. Wärme- und Stoffübertragung 27, 217–223 (1992). https://doi.org/10.1007/BF01589919

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  • DOI: https://doi.org/10.1007/BF01589919

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