Heat transfer coefficients and the resulting heat flux reduction due to film cooling on a flat plate downstream a row of cylindrical holes are investigated. Highly resolved two-dimensional heat transfer coefficient distributions were measured by means of infrared thermography and carefully corrected for local internal testplate conduction and radiation effects. These locally acquired data are processed to lateral average heat transfer coefficients for a quantitative assessment. A wide range variation of the flow parameters blowing rate and density ratio as well as the geometrical parameters streamwise ejection angle and hole spacing is examined. The effects of these dominating parameters on the heat transfer augmentation from film cooling are discussed and interpreted with the help of highly resolved surface results of effectiveness and heat transfer coefficients presented earlier. A new method of evaluating the heat flux reduction from film cooling is presented. From a combination of the lateral average of both the adiabatic effectiveness and the heat transfer coefficient, the lateral average heat flux reduction is processed according to the new method. The discussion of the total effect of film cooling by means of the heat flux reduction reveals important characteristics and constraints of discrete hole ejection. The complete heat transfer data of all measurements are used as basis for a new correlation of lateral average heat transfer coefficients. This correlation combines the effects of all the dominating parameters. It yields a prediction of the heat transfer coefficient from the ejection position to far downstream, including effects of extreme blowing angles and hole spacing. The new correlation has a modular structure to allow for future inclusion of additional parameters. Together with the correlation of the adiabatic effectiveness it provides an immediate determination of the streamwise heat flux reduction distribution of cylindrical hole film-cooling configurations.

Issue Section:
Technical Papers
Keywords:
gas turbines, cooling, heat transfer, film flow, flow measurement, jets, temperature measurement
Topics:
Density, Heat flux, Heat transfer, Heat transfer coefficients, Flow (Dynamics), Film cooling, Cooling, Coolants
1.
Baldauf
,
S.
,
Schulz
,
A.
, and
Wittig
,
S.
,
2001
, “
High Resolution Measurements of Local Heat Transfer Coefficients From Discrete Hole Film Cooling
,”
ASME J. Turbomach.
,
123
, pp.
749
–
757
.
2.
Baldauf
,
S.
,
Schulz
,
A.
, and
Wittig
,
S.
,
2001
, “
High-Resolution Measurements of Local Effectiveness From Discrete Hole Film Cooling
,”
ASME J. Turbomach.
,
123
, pp.
758
–
765
.
3.
Metzger
,
D. E.
,
Carper
,
H. J.
, and
Swank
,
L. R.
,
1968
, “
Heat Transfer With Film Cooling Near Nontangential Injection Slots
,”
ASME J. Eng. Power
,
80
, pp.
157
–
163
.
4.
Metzger
,
D. E.
, and
Fletcher
,
D. D.
,
1971
, “
Evaluation of Heat Transfer for Film-Cooled Turbine Components
,”
ASME J. Eng. Power
,
8
, pp.
181
–
184
.
5.
Metzger
,
D. E.
,
Carper
,
H. J.
, and
Warren
,
J. M.
,
1972
, “
Predicted Film Cooling Near Flush Slots-Comparison With Experiment
,”
J. Aircr.
,
9
, pp.
857
–
863
.
6.
Choe, H., Kays, W. M., and Moffat, R. J., 1974, “The Superposition Approach to Film-Cooling,” ASME Paper 74-WA/HT-27.
7.
Loftus
,
P. J.
, and
Jones
,
T. V.
,
1983
, “
The Effect of Temperature Ratios on the Film Cooling Process
,”
ASME J. Eng. Power
,
105
, pp.
615
–
620
.
8.
Forth, C. J. P., Loftus, P. J., and Jones, T. V., 1985, “The Effect of Density Ratio on the Film Cooling of a Flat Plate,” Heat Transfer and Cooling in Gas Turbines, AGARD-CP-390, Paper 10.
9.
Teekaram
,
A. J. H.
,
Forth
,
C. J. P.
, and
Jones
,
T. V.
,
1989
, “
The Use of Foreign Gas to Simulate the Effects of Density Ratios in Film Cooling
,”
ASME J. Turbomach.
,
111
, pp.
57
–
62
.
10.
Gritsch, M., Baldauf, S., Martiny, M., Schulz, A., and Wittig, S., 1999, “The Superposition Approach to Local Heat Transfer Coefficients in High Density Ratio Film Cooling Flows,” ASME Paper 99-GT-168.
11.
Eckert
,
E. R. G.
,
1984
, “
Analysis of Film Cooling and Full-Coverage Film Cooling of Gas Turbine Blades
,”
ASME J. Eng. Gas Turbines Power
,
106
, pp.
206
–
213
.
12.
Baldauf, S., and Scheurlen, M., 1996, “CFD Based Sensitivity Study of Flow Parameters for Engine Like Film Cooling Conditions,” ASME Paper 96-GT-310.
13.
Martiny, M., Schiele, R., Gritsch, M., Schulz, A., and Wittig, S., 1996, “In Situ Calibration for Quantitative Infrared Thermography,” Quirt’96 Eurotherm No. 50, Stuttgart, Germany, Sept. 2–5.
14.
Kays, W. M., and Crawford, M. E., 1980, Convective Heat and Mass Transfer, McGraw Hill, New York, NY.
15.
Baldauf
,
S.
,
Scheurlen
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
,
2002
, “
Correlation of Film-Cooling Effectiveness From Thermographic Measurements at Enginelike Conditions
,” GT-2002-30180,
ASME J. Turbomach.
,
124
, pp.
686
–
698
.
16.
Eriksen
,
V. L.
, and
Goldstein
,
R. J.
,
1974
, “
Heat Transfer and Film Cooling Following Injection Through Inclined Circular Tubes
,”
ASME J. Heat Transfer
,
96
, pp.
239
–
245
.
17.
Hay
,
N.
,
Lampard
,
D.
, and
Saluja
,
C. L.
,
1985
, “
Effects of Cooling Films and the Heat Transfer Coefficient on a Flat Plate With Zero Mainstream Pressure Gradient
,”
ASME J. Eng. Gas Turbines Power
,
107
, pp.
105
–
110
.
18.
Ammari
,
H.
,
Hay
,
N.
, and
Lampard
,
D.
,
1990
, “
The Effect of Density Ratio on the Heat Transfer Coefficient From a Film-Cooled Flat Plate
,”
ASME J. Turbomach.
,
112
, pp.
444
–
450
.
19.
Goldstein, R. J., Jin, P., and Olson, R. L., 1998, “Film Cooling Effectiveness and Mass/Heat Transfer Downstream of One Row of Discrete Holes,” ASME Paper 98-GT-174.
20.
Drost, U., Bo¨lcs, A., and Hoffs, A., 1997, “Utilization of the Transient Liquid Crystal Technique for Film Cooling Effectiveness and Heat Transfer Investigations on a Flat Plate and a Turbine Airfoil,” ASME Paper 97-GT-26.
21.
Burd, S. W., Kaszeta, R. W., and Simon, T. W., 1996, “Measurements in Film Cooling Flows: Hole L/D and Turbulence Intensity Effects,” ASME Paper 96-WA/HT-7.
22.
Sen
,
B.
,
Schmidt
,
D. L.
, and
Bogard
,
D. G.
,
1996
, “
Film Cooling with Compound Angle Holes: Heat Transfer
,”
ASME J. Turbomach.
,
118
, pp.
800
–
806
.
23.
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
, pp.
293
–
3066
24.
Forth, C. J. P., and Jones, T. V., 1986, “Scaling Parameters in Film Cooling,” Proc. 8th Int. Heat Transfer Conference, Vol. 3, pp. 1271–1276.
25.
Seban
,
R. A.
,
1960
, “
Heat Transfer and Effectiveness for a Turbulent Boundary Layer With Tangential Fluid Injection
,”
ASME J. Heat Transfer
,
82
, pp.
309
–
312
.
26.
Jabbari
,
M. Y.
, and
Goldstein
,
R. J.
,
1978
, “
Adiabatic Wall Temperature and Heat Transfer Downstream of Injection Through Two Rows of Holes
,”
ASME J. Eng. Power
,
100
, pp.
303
–
307
.
27.
Bittlinger, G., Schulz, A., and Wittig, S., 1994, “Film Cooling Effectiveness and Heat Transfer Coefficients for Slot Injection at High Blowing Ratios,” ASME Paper 94-GT-182.
28.
Goldstein
,
R. J.
, and
Taylor
,
J. R.
,
1982
, “
Mass Transfer in the Neighborhood of Jets Entering a Crossflow
,”
ASME J. Heat Transfer
,
104
, pp.
715
–
721
.
Copyright © 2002
 by ASME
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