Detailed measurements of the heat transfer coefficient (htc) distributions on the internal surfaces of a novel gas turbine blade cooling configuration were carried out using a transient liquid crystal technique. The cooling geometry, in which a series of racetrack passages are connected to a central plenum, provides high heat transfer coefficients in regions of the blade in good thermal contact with the outer blade surface. The Reynolds number changes along its length because of the ejection of fluid through a series of 19 transfer holes in a staggered arrangement, which are used to connect ceramic cores during the casting process. Heat transfer coefficient distributions on these holes surface are particularly important in the prediction of blade life, as are heat transfer coefficients within the hole. The results at passage inlet Reynolds numbers of 21,667, 45,596, and 69,959 are presented along with in-hole htc distributions at Rehole=5930, 12,479, 19,147; and suction ratios of 0.98, 1.31, 2.08, and 18.67, respectively. All values are engine representative. Characteristic regions of high heat transfer downstream of the transfer holes were observed with enhancement of up to 92% over the Dittus–Boelter level. Within the transfer holes, the average htc level was strongly affected by the cross-flow at the hole entrance. htc levels were low in these short (l/d=1.5) holes fed from regions of developed boundary layer.

1.
Dailey
,
G. M.
, 2000, “
Aero-Thermal Performance of Integral Cooling Systems in Turbomachines: Design and Calculation Issues
,”
VKI Lecture Series
, Feb. 28–Mar. 3.
2.
Ireland
,
P. T.
, and
Jones
,
T. V.
, 1986, “
Detailed Measurements of Heat Transfer on and Around a Pedestal in Fully Developed Channel Flow
,”
Proceedings of the Eighth International Heat Transfer Conference
, San Francisco, CA, pp.
975
986
.
3.
Miller
,
D. S.
, 1990,
Internal Flow Systems
, 2nd. ed.,
BHR Group Ltd.
,
Cranfield, UK
.
4.
Wesley
,
D. A.
, and
Sparrow
,
E. M.
, 1976, “
Circumferentially Local and Average Turbulent Heat-Transfer Coefficients in a Tube Downstream of a Tee
,”
Int. J. Heat Mass Transfer
0017-9310,
19
, pp.
1205
1214
.
5.
Ainsworth
,
R. W.
, and
Jones
,
T. V.
, 1979, “
Measurement of Heat Transfer in Circular, Rectangular, and Triangular Ducts, Representing Typical Turbine Blade Internal Cooling Passages Using Transient Techniques
,” ASME Paper No. 79-GT-40.
6.
Sparrow
,
E. M.
, and
Kemink
,
R. G.
, 1979, “
Heat Transfer Downstream of a Fluid Withdrawal Branch in a Tube
,”
ASME J. Heat Transfer
0022-1481,
101
,
23
28
.
7.
Byerley
,
A. R.
, 1989, “
Heat Transfer Near the Entrance to a Film Cooling Hole in a Gas Turbine Blade
,” Ph.D. thesis, Department of Engineering Science, University of Oxford, Oxford, UK.
8.
Shen
,
J. R.
,
Ireland
,
P. T.
,
Wang
,
Z.
, and
Jones
,
T.
, 1991, “
Heat Transfer Coefficient Enhancement in a Gas Turbine Blade Cooling Passage Due to Film Cooling Holes
,”
Turbomachinery: Latest Developments in a Changing Scene
,
IMechE
,
London
, pp.
219
226
.
9.
Gillespie
,
D. R. H.
,
Byerley
,
A. R.
,
Wang
,
Z.
,
Ireland
,
P. T.
,
Jones
,
T. V.
, and
Kohler
,
S. T.
, 1996, “
Detailed Measurements of Local Heat Transfer Coefficient in the Entrance to Normal and Inclined Film Cooling Holes
,”
ASME J. Turbomach.
0889-504X,
118
, pp.
285
290
.
10.
Boelter
,
L. M. K.
,
Young
,
G.
, and
Iversen
,
H. W.
, 1948, “
An Investigation of Aircraft Heaters XXVII: The Distribution of Heat Transfer Rate in the Entrance Region of a Circular Tube
,” NACA Report No. TN 1451.
11.
Goldstein
,
R. J.
,
Cho
,
H. H.
, and
Jabbari
,
M. Y.
, 1997, “
Effect of Plenum Crossflow on Heat (Mass) Transfer Near and Within the Entrance of Film Cooling Holes
,”
ASME J. Turbomach.
0889-504X,
119
, pp.
761
769
.
12.
Andrews
,
G. E.
, and
Mkpadi
,
M. C.
, 1983, “
Full Coverage Discrete Hole Wall Cooling: Discharge Coefficients
,”
International Gas Turbine Conference and Exhibit
, Phoenix, AZ, Mar.
13.
Abu Talib
,
A. R.
,
Ireland
,
P. T.
,
Neely
,
A. J.
, and
Mullender
,
A. J.
, 2003, “
A Novel Liquid Crystal Image Processing Technique Using Multiple Gas Temperature Tests to Determine Heat Transfer Coefficient Distribution and Adiabatic Wall Temperature
,” ASME Paper No. GT2003-38198.
14.
Schultz
,
D. L.
, and
Jones
,
T. V.
, 1973, “
Heat Transfer Measurements in Short Duration Hypersonic Facilities
,” AGARDograph No. 165.
15.
Ieronymidis
,
I.
,
Gillespie
,
D. R. H.
,
Ireland
,
P. T.
, and
Kingston
,
R.
, 2006, “
Experimental and Computational Flow Field Studies of an Integrally Cast Cooling Manifold With and Without Rotation
,”
Turbo Expo 2006: Power for Land, Sea & Air
, Barcelona, Spain, May 8–11.
16.
Moffat
,
R. J.
, 1988, “
Describing the Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
0894-1777,
1
, pp.
3
17
.
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