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Research Papers

Simulations of Slot Film-Cooling With Freestream Acceleration and Turbulence

[+] Author and Article Information
Yousef Kanani

Illinois Institute of Technology,
Mechanical, Materials and Aerospace
Engineering Department,
Chicago, IL 60616
e-mail: ykanani@hawk.iit.edu

Sumanta Acharya

Illinois Institute of Technology,
Mechanical, Materials and Aerospace
Engineering Department,
Chicago, IL 60616
e-mail: sacharya1@iit.edu

Forrest Ames

Mechanical Engineering Department,
University of North Dakota,
Grand Forks, ND 58202
e-mail: forrest.ames@engr.und.edu

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received September 11, 2017; final manuscript received December 4, 2017; published online January 30, 2018. Editor: Kenneth C. Hall.

J. Turbomach 140(4), 041005 (Jan 30, 2018) (11 pages) Paper No: TURBO-17-1156; doi: 10.1115/1.4038877 History: Received September 11, 2017; Revised December 04, 2017

Slot film cooling in an accelerating boundary layer with high freestream turbulence is studied numerically using large eddy simulations (LES). Calculations are done for a symmetrical leading edge geometry with the slot fed by a plenum populated with pin fins. The synthetic eddy method is used to generate different levels of turbulence and length scales at the inflow cross-plane. Calculations are done for a Reynolds number of 250,000 and freestream turbulence levels of 0.7%, 3.5%, 7.8%, and 13.7% to predict both film cooling effectiveness and heat transfer coefficient over the test surface. These conditions correspond to the experimental measurements of (Busche, M. L., Kingery, J. E., and Ames, F. E., 2014, “Slot Film Cooling in an Accelerating Boundary Layer With High Free-Stream Turbulence,” ASME Paper No. GT2014-25360.) Numerical results show good agreement with measurements and show the observed decay of thermal effectiveness and increase of Stanton number with turbulence intensity. Velocity and turbulence exiting the slot are nonuniform laterally due to the presence of pin fins in the plenum feeding the slot which creates a nonuniform surface temperature distribution. No transition to fully turbulent boundary layer is observed throughout the numerical domain. However, freestream turbulence increases wall shear stress downstream driving the velocity profiles toward the turbulent profile and counteracts the laminarizing effects of the favorable pressure gradient. The effective Prandtl number decreases with freestream turbulence. The temperature profiles deviate from the self-similar profile measured under low freestream turbulence condition, reflecting the role of the increased diffusivity in the boundary layer at higher freestream turbulence.

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References

Bunker, R. S. , 2011, “A Study of Mesh-Fed Slot Film Cooling,” ASME J. Turbomach., 133(1), p. 011022. [CrossRef]
Busche, M. L. , Kingery, J. E. , and Ames, F. E. , 2014, “Slot Film Cooling in an Accelerating Boundary Layer With High Free-Stream Turbulence,” ASME Paper No. GT2014-25360.
Wieghardt, K. , 1946, “Hot-Air Discharge for De-Icing,” AAF Translation, Wright Field, OH, Report No. F-TS-919-RE.
Hartnett, J. P. , Birkebak, R. C. , and Eckert, E. R. G. , 1961, “Velocity Distributions, Temperature Distributions, Effectiveness and Heat Transfer for Air Injected Through a Tangential Slot Into a Turbulent Boundary Layer,” ASME J. Heat Transfer, 83(3), pp. 293–305. [CrossRef]
Goldstein, R. J. , and Haji-Sheikh, A. , 1967, “Prediction of Film Cooling Effectiveness,” JSME 1967 Semi-International Symposium, Tokyo, Japan, Sept. 4–8, pp. 213–218.
Seban, R. A. , 1960, “Heat Transfer and Effectiveness for a Turbulent Boundary Layer With Tangential Fluid Injection,” ASME J. Heat Transfer, 82(4), pp. 303–312. [CrossRef]
Spalding, D. B. , 1965, “Prediction of Adiabatic Wall Temperatures in Film-Cooling Systems,” AIAA J., 3(5), pp. 965–967. [CrossRef]
Hartnett, J. P. , 1985, “Mass Transfer Cooling,” Handbook of Heat Transfer Applications, W. M. Rohsenow , J. P. Hartnett , and E. N. Ganic , eds., McGraw-Hill, NewYork.
Goldstein, R. J. , 1971, “Film Cooling,” Advances in Heat Transfer, Vol. 7, B. S. Jone and R. Z. Smith , eds., Academic Press, New York, pp. 321–379. [CrossRef]
Acharya, S. , and Kanani, Y. , 2017, “Advances in Film Cooling Heat Transfer,” Advances in Heat Transfer, Vol. 49, E. M. Sparrow , J. P. Abraham , and J. M. Gorman , eds., Academic Press, Cambridge, MA, pp. 91–156. [CrossRef]
Teekaram, A. J. H. , Forth, C. J. P. , and Jones, T. V. , 1991, “Film Cooling in the Presence of Mainstream Pressure Gradients,” ASME J. Turbomach., 113(3), pp. 484–492. [CrossRef]
Carlson, L. W. , and Talmor, E. , 1968, “Gaseous Film Cooling at Various Degrees of Hot-Gas Acceleration and Turbulence Levels,” Int. J. Heat Mass Transfer, 11(11), pp. 1695–1713. [CrossRef]
Kacker, S. C. , and Whitelaw, J. H. , 1968, “The Effect of Slot Height and Slot-Turbulence Intensity on the Effectiveness of the Uniform Density, Two-Dimensional Wall Jet,” ASME J. Heat Transfer, 90(4), pp. 469–475. [CrossRef]
Kacker, S. C. , and Whitelaw, J. H. , 1969, “An Experimental Investigation of the Influence of Slot-Lip-Thickness on the Impervious-Wall Effectiveness of the Uniform-Density, Two-Dimensional Wall Jet,” Int. J. Heat Mass Transfer, 12(9), pp. 1196–1201. [CrossRef]
Kanani, Y. , and Acharya, S. , 2016, “Numerical Investigation of Slot Film Cooling Over a Flat Plate—Part 2: Plenum Turbulence Effect,” HT/FE/ICNMM Conferences, Washington DC, July 10–14.
Simon, F. F. , 1986, “Jet Model for Slot Film Cooling With Effect of Free-Stream and Coolant Turbulence,” NASA Lewis Research Center, Washington, DC, Report No. NASA-TP-2655. https://ntrs.nasa.gov/search.jsp?R=19870008601
Lebedev, V. P. , Lemanov, V. V. , Misyura, S. Y. , and Terekhov, V. I. , 1995, “Effects of Flow Turbulence on Film Cooling Efficiency,” Int. J. Heat Mass Transfer, 38(11), pp. 2117–2125. [CrossRef]
Jarrin, N. , Benhamadouche, S. , Laurence, D. , and Prosser, R. , 2006, “A Synthetic-Eddy-Method for Generating Inflow Conditions for Large-Eddy Simulations,” Int. J. Heat Fluid Flow, 27(4), pp. 585–593. [CrossRef]
Lilly, D. K. , 1992, “A Proposed Modification of the Germano-Subgrid-Scale Closure Method,” Phys. Fluids a-Fluid Dyn., 4(3), pp. 633–635. [CrossRef]
Hunt, J. C. R. , Wray, A. A. , and Moin, P. , 1988, “Eddies, Streams, and Convergence Zones in Turbulent Flows,” Summer Program Center for Turbulence Research, Stanford University, Stanford, CA, pp. 193–208. http://adsabs.harvard.edu/abs/1988stun.proc..193H
Nagarajan, S. , Lele, S. K. , and Ferziger, J. H. , 2007, “Leading-Edge Effects in Bypass Transition,” J. Fluid Mech., 572, pp. 471–504. [CrossRef]
Goldstein, M. E. , and Sescu, A. , 2008, “Boundary-Layer Transition at High Free-Stream Disturbance Levels—Beyond Klebanoff Modes,” J. Fluid Mech., 613, pp. 95–124. [CrossRef]
Marusic, I. , McKeon, B. J. , Monkewitz, P. A. , Nagib, H. M. , Smits, A. J. , and Sreenivasan, K. R. , 2010, “Wall-Bounded Turbulent Flows at High Reynolds Numbers: Recent Advances and Key Issues,” Phys. Fluids, 22(6), p. 065103.
Piomelli, U. , Balaras, E. , and Pascarelli, A. , 2000, “Turbulent Structures in Accelerating Boundary Layers,” J. Turbul., 1, pp. 1–16. [CrossRef]
Castillo, L. , and Wang, X. , 2004, “Similarity Analysis for Nonequilibrium Turbulent Boundary Layers,” ASME J. Fluids Eng., 126(5), pp. 827–834. [CrossRef]
Samson, A. , and Sarkar, S. , 2015, “Effects of Free-Stream Turbulence on Transition of a Separated Boundary Layer Over the Leading-Edge of a Constant Thickness Airfoil,” ASME J. Fluids Eng., 138(2), p. 021202. [CrossRef]
Thole, K. A. , and Bogard, D. G. , 1996, “High Freestream Turbulence Effects on Turbulent Boundary Layers,” ASME J. Fluids Eng., 118(2), pp. 276–284. [CrossRef]
Stefes, B. , and Fernholz, H.-H. , 2004, “Skin Friction and Turbulence Measurements in a Boundary Layer With Zero-Pressure-Gradient Under the Influence of High Intensity Free-Stream Turbulence,” Eur. J. Mech.-B/Fluids, 23(2), pp. 303–318. [CrossRef]
Sunden, B. , 1979, “A Theoretical Investigation of the Effect of Freestream Turbulence on Skin Friction and Heat Transfer for a Bluff Body,” Int. J. Heat Mass Transfer, 22(7), pp. 1125–1135. [CrossRef]
Bons, J. P. , 2002, “St and Cf Augmentation for Real Turbine Roughness With Elevated Freestream Turbulence,” ASME J. Turbomach., 124(4), pp. 632–644. [CrossRef]
Schlichting, H. , 1979, Boundary-Layer Theory, McGraw-Hill, New York.
Ludwieg, H. , and Tillmann, W. , 1950, “Investigation of the Wall-Shearing Stress in Turbulent Boundary Layers,” National Advisory Committee for Aeronautics, Washington, DC, Report No. NACA-TM-1285. https://ntrs.nasa.gov/search.jsp?R=19930093945
Achenbach, E. , 1968, “Distribution of Local Pressure and Skin Friction Around a Circular Cylinder in Cross-Flow Up to Re = 5 × 106,” J. Fluid Mech., 34(4), pp. 625–639. [CrossRef]

Figures

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Fig. 1

(a) Leading edge and test surface profile. The gray area shows the numerical domain. (b) The periodic module of the pin-finned plenum delivering coolant to the slot. The figure on the right shows the side view of the finned plenum and the slot-delivery channel; pin fins are indicated by the darkened regions. The a priori simulation data at plane section A-A are used as inflow conditions for the main simulations.

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Fig. 2

Acceleration parameter distribution with surface distance reported by Busche et al. [2]

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Fig. 3

Grid independence showing time- and laterally-averaged slot film cooling effectiveness

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Fig. 4

Numerical predictions of the time- and laterally-averaged adiabatic film cooling effectiveness at four turbulence levels

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Fig. 5

Comparison of slot film cooling effectiveness measurements and predictions with Hartnett's and Simon's correlations [4,16]: (a) Tu = 0.7%, (b) Tu = 3.5%, (c) Tu = 7.8%, and (d) Tu = 13.7%

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Fig. 6

Comparison of the predicted Stanton number distribution with measurements [2] over the surface

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Fig. 7

Contours of the time-averaged temperature field (or effectiveness) over the test surface for four freestream turbulence conditions

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Fig. 8

Contours of (a) the turbulence kinetic energy and (b) the blowing ratio at the slot exit (section B-B in Fig. 1)

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Fig. 9

Time-averaged velocity contour along a streamwise plane at a spanwise location of z/s = 3.75

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Fig. 10

Cooling effectiveness and blowing ratio. Main flow direction is from bottom to top. Bottom section shows blowing ratio distribution at the slot exit.

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Fig. 11

Iso-surfaces of the Q at the intermediate value colored by instantaneous velocity

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Fig. 12

Iso-surfaces of the Q at the high value colored by instantaneous velocity—Pin fins shown in this plot are not part of the main numerical simulation domain but accounted for in a priory simulation to specify slot inflow conditions

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Fig. 13

The time- and laterally-averaged streamwise velocity profiles scaled with the edge velocity Ue at various locations as a function of wall-normal coordinate scaled by the slot height y/s. See Fig. 16 for legend.

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Fig. 14

Velocity profiles in inner wall coordinates compared with viscous sublayer profile and universal log-law (gray dashed lines). See Fig. 16 for legend.

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Fig. 15

Distribution of integral quantities of the time- and laterally-averaged boundary layer: displacement thickness δ*, Shape factor H and Clauser parameter G. See Fig. 16 for legend.

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Fig. 16

Time- and laterally-averaged skin friction distribution over the test surface. Ludwieg and Tillmann correlation [32] (gray lines)—line types correspond to different turbulence levels.

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Fig. 17

Time- and laterally-averaged wall shear stress scaled with inlet velocity and Reynolds number

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Fig. 18

Evolution of the peak of the laterally averaged streamwise turbulence intensity over the surface

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Fig. 19

Laterally averaged shear stress profile as a function of y+ and y/s at various X/s (Tu = 7.8%)

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Fig. 20

Laterally averaged (a) streamwise and (b) wall normal turbulence intensity profiles

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Fig. 21

Turbulence intensity profiles at X/s = −5 (upstream of the slot) for Tu = 7.8%

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Fig. 22

Fully developed nondimensional temperature profiles for various turbulence levels

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Fig. 23

Thermal boundary layer growth at different turbulence levels

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