The local heat transfer inside the entrance to large-scale models of film cooling holes has been measured using the transient heat transfer technique. The method employs temperature-sensitive liquid crystals to measure the surface temperature of large-scale perspex models. Full distributions of local Nusselt number were calculated based on the cooling passage centerline gas temperature ahead of the cooling hole. The circumferentially averaged Nusselt number was also calculated based on the local mixed bulk driving gas temperature to aid interpretation of the results, and to broaden the potential application of the data. Data are presented for a single film cooling hole inclined at 90 and 150 deg to the coolant duct wall. Both holes exhibited entry length heat transfer levels that were significantly lower than those predicted by entry length data in the presence of crossflow. The reasons for the comparative reduction are discussed in terms of the interpreted flow field.

Issue Section:
Research Papers
Topics:
Film cooling, Heat transfer coefficients, Temperature, Cooling, Heat transfer, Coolants, Ducts, Flow (Dynamics), Liquid crystals, Transient heat transfer
1.
Baughn, J. W., and Yan, X., 1992, “Heat Transfer Measurements in Square Ducts With Transverse Ribs,” presented at the National Heat Transfer Conference, Aug.
2.
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 TN1451, Washington, DC.
3.
Byerley, A. R., Ireland, P. T., Jones, T. V., and Ashton, S. A., 1988, “Detailed Heat Transfer Measurements Near and Within the Entrance of a Film Cooling Hole,” ASME Paper No. 88-GT-155.
4.
Byerley, A. R., Jones, T. V., and Ireland, P. T., 1992, “Internal Cooling Passage Heat Transfer Near the Entrance to a Film Cooling Hole: Experimental and Computational Results,” ASME Paper No. 92-GT-241.
5.
Byerley, A. R., 1989, “Heat Transfer Near the Entrance to a Film Cooling Hole in a Gas Turbine Blade,” D. Phil Thesis, Department of Engineering Science, University of Oxford, United Kingdom.
6.
Dunne, S. T., 1982, “A Study of Flow and Heat Transfer in Gas Turbine Blade Cooling Passages,” D. Phil Thesis, Department of Engineering Science, University of Oxford, United Kingdom.
7.
Haidar
N. I. A.
, and
Dixon
S. L.
,
1988
, “
Compressible Flow Losses in Branched Ducts
,”
ASME
HTD-Vol.
104
, No.
2
, pp.
17
–
23
.
8.
Ireland, P. T., and Jones, T. V., 1985, “The Measurement of Local Heat Transfer Coefficients in Blade Cooling Geometries,” presented at the AGARD Conference on Heat Transfer and Cooling in Gas Turbines, CP 390, Paper 28.
9.
Ireland, P. T., 1987, “Internal Cooling of Turbine Blades,” D. Phil Thesis, Department of Engineering Science, University of Oxford, United Kingdom.
10.
Metzger, D. E., and Cordaro, J. V., 1979, “Heat Transfer in Short Tubes Supplied From a Cross-Flowing Stream,” ASME Paper No. 79-WA/HT-16.
11.
Morland, L. C., 1989, “Mathematical Models for a Fluid Flow Arising in Turbine Blade Cooling Passages,” D. Phil Thesis, University of Oxford, United Kingdom.
12.
Shen, J.-R., Ireland, P. T., Wang, Z., and Jones, T. V., 1991, “Heat Transfer Coefficient Enhancement in a Gas Turbine Blade Cooling Passage Due to Film Cooling Holes,” Proceedings of the Institution of Mechanical Engineers, Turbo-machinery, London, pp. 219–226.
13.
Shen, J.-R., Ireland, P. T., Wang, Z., and Jones, T. V., 1994, “Heat Transfer Enhancement Within a Turbine Blade Cooling Passage Using Ribs and Combinations of Ribs With Film Cooling Holes,” ASME Paper No. 94-GT-232; accepted for publication in the ASME JOURNAL OF TURBOMACHINERY.
14.
Vedula, R. J., and Metzger, D. E., “A Method for the Simultaneous Determination of Local Effectiveness and Heat Transfer Distributions in Three-Temperature Convection Situations,” ASME Paper No. 91-GT-345.
15.
Wang, Z., 1991, “The Application of Thermochromatic Liquid Crystals to Detailed Turbine Cooling Measurements,” D. Phil Thesis, Department of Engineering Science, University of Oxford, United Kingdom.
16.
Wang
Z.
,
Ireland
P. T.
, and
Jones
T. V.
,
1995
, “
An Advanced Method of Processing Liquid Crystal Video Signals From Transient Heat Transfer Experiments
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
117
, pp.
184
–
189
.
17.
Yan
X.
,
Baughan
J. W.
, and
Mesbah
M.
,
1992
, “
The Effect of Reynolds Number on the Heat Transfer Distribution From a Flat Plate to an Impinging Jet
,”
ASME
HTD-Vol.
226
, pp.
1
–
8
.
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