A detailed investigation on the effect of squealer geometries on the blade tip leakage flow and associated heat transfer is presented for a scaled up high pressure turbine blade in a low-speed wind tunnel facility. The linear cascade is made of four blades with the two corner blades acting as guides. The tip profile of a first stage rotor blade is used to fabricate the two-dimensional blade. The wind tunnel accommodates an 116° turn for the blade cascade. The mainstream Reynolds number based on the axial chord length based on cascade exit velocity is 4.83×105. An upstream wake effect is simulated with a spoked wheel wake generator placed upstream of the cascade. A turbulence grid placed even farther upstream generates a free-stream turbulence of 4.8%. The center blade has a tip clearance gap of 1.56% with respect to the blade span. Static pressure measurements are obtained on the blade surface and the shroud. Results show that the presence of the squealer alters the tip gap flow field significantly and produces lower overall heat transfer coefficients. The effects of different squealer arrangements are basically to study the effect of squealer rim placement on tip leakage flow and associated heat transfer. Detailed heat transfer measurements are obtained using a steady state liquid crystal technique. The effect of periodic unsteady wake effect is also investigated by varying the wake Strouhal number from 0–0.4. Results show that suction side squealers may be favorable in terms of overall reduction in heat transfer coefficients over the tip surface. However, the presence of a full squealer is most beneficial in terms of reducing overall heat load on the tip surface. There is reasonable effect of wake induced periodicity on tip heat transfer.

1.
Bindon
,
J. P.
,
1989
, “
The Measurement and Formation of Tip Clearance Loss
,”
ASME J. Turbomach.
,
111
, pp.
257
263
.
2.
Morphis, G., and Bindon, J. P., 1988, “The Effect of Relative Motion, Blade Edge Radius and Gap Size on the Blade Tip Pressure Distribution in an Annular Turbine Cascade with Clearance,” AMSE Paper 88-GT-256.
3.
Yaras
,
M.
,
Yingkang
,
Z.
, and
Sjolander
,
S. A.
,
1989
, “
Flow Field in the Tip Gap of a Planar Cascade of Turbine Blades
,”
ASME J. Turbomach.
,
111
, pp.
276
283
.
4.
Yamamoto
,
A.
,
1989
, “
Endwall Flow/Loss Mechanisms in a Linear Turbine Cascade With Blade Tip Clearance
,”
ASME J. Turbomach.
,
111
, pp.
264
275
.
5.
Kaiser, I., and Bindon, J. P., 1997, “The Effect of Tip Clearance on the Development of Loss Behind a Rotor and a Subsequent Nozzle,” ASME Paper 97-GT-53.
6.
Mayle, R. E., and Metzger, D. E., 1982, “Heat Transfer at the Tip of an Unshrouded Turbine Blade,” Proceedings of the 7th International Heat Transfer Conference, 3, pp. 87–92.
7.
Metzger
,
D. E.
,
Bunker
,
R. S.
, and
Chyu
,
M. K.
,
1989
, “
Cavity Heat Transfer on a Transverse Grooved Wall in a Narrow Flow Channel
,”
ASME J. Heat Transfer
,
111
, pp.
73
79
.
8.
Chyu
,
M. K.
,
Moon
,
H. K.
, and
Metzger
,
D. E.
,
1989
, “
Heat Transfer in the Tip Region of Grooved Turbine Blades
,”
ASME J. Turbomach.
,
111
, pp.
131
138
.
9.
Metzger, D. E., Dunn, M. G., and Hah, C., 1990, “Turbine Tip and Shroud Heat Transfer,” Proceeding of International Gas Turbine and Aeroengine Congress and Exposition, Brussels, Belgium, September 1990, Paper No. 90-GT-333.
10.
Yang, T. T., and Diller, T. E., 1995, “Heat Transfer and Flow for a Grooved Turbine Blade Tip in a Transonic Cascade,” Proceedings of International Mechanical Engineering Congress and Exposition, San Francisco, ASME Paper No. 95-WA/HT-29.
11.
Bunker
,
R. S.
,
Bailey
,
J. C.
, and
Ameri
,
A. A.
,
1999
, “
Heat Transfer and Flow on the First Stage Blade Tip of a Power Generation Gas Turbine: Part 1—Experimental Results
,”
ASME J. Turbomach.
,
122
, pp.
263
271
.
12.
Ameri
,
A. A.
, and
Bunker
,
R. S.
,
1999
, “
Heat Transfer and Flow on the First Stage Blade Tip of a Power Generation Gas Turbine: Part 2—Simulation Results
,”
ASME J. Turbomach.
,
122
, pp.
272
277
.
13.
Azad, Gm. S., Han, J. C., and Teng, S., 2000, “Heat Transfer and Pressure Distributions on a Gas Turbine Blade Tip,” Proceedings of International Gas Turbine and Aeroengine Congress and Exposition, ASME paper 2000-GT-194.
14.
Azad, G. S., Han, J. C., and Boyle, R. J., 2000, “Heat Transfer and Flow on the Squealer Tip of a Gas Turbine Blade,” Proceedings of International Gas Turbine and Aeroengine Congress and Exposition, Munich, Germany, 2000-GT-195.
15.
Bunker, R. S., and Bailey, J. C., 2001, “Effect of Squealer Cavity Depth and Oxidation on Turbine Blade Tip Heat Transfer,” International Gas Turbine and Aeroengine Congress and Exposition, New Orleans, June 2001.
16.
Azad, G. S., Han, J. C., Bunker, R. S., and Lee, C. P., 2001, “Effect of Squealer Geometry Arrangement on Gas Turbine Blade Tip Heat Transfer,” Proceedings of International Mechanical Engineering Congress and Exposition, New York, New York, November 2001, IMECE2001/HTD-2431.
17.
Dunn, M. G., and Haldeman, C. W., 2000, “Time-Averaged Heat Flux for a Recessed Tip, Lip and Platform of a Transonic Turbine Blade,” ASME Paper 2000-GT-0197.
18.
Nasir, H., Ekkad, S. V., Kontrovitz, D. M., Bunker, R. S., and Prakash, C., 2003, “Effect of Tip Gap and Squealer Geometry on Detailed Heat Transfer Measurements over a HPT Rotor Blade Tip,” IMECE 2003-41294, ASME IMECE 2003, Washington, D.C.
19.
Wittig, S., Schulz, A., Dullenkopf, K., and Fairbank, J., 1988, “Effects of Free-Stream Turbulence and Wake Characteristics on the Heat Transfer Along a Cooled gas Turbine Blade,” ASME Paper No. 88-GT-179.
20.
Han
,
J. C.
,
Zhang
,
L.
, and
Ou
,
S.
,
1993
, “
Influence of Unsteady Wake on Heat Transfer Coefficient from a Gas Turbine Blade
,”
ASME J. Heat Transfer
,
115
, pp.
904
911
.
21.
Teng
,
S.
,
Han
,
J. C.
, and
Azad
,
Gm. S.
,
2001
, “
Detailed Heat Transfer Coefficient Distributions on a Large Scale Gas Turbine Blade Tip
,”
ASME J. Heat Transfer
,
123
, pp.
803
809
.
22.
Saxena, V., Nasir, H., and Ekkad, S. V., 2003, “Effect of Blade Tip Geometry on Tip Flow and Heat Transfer for a Blade in a Low Speed Cascade,” ASME GT2003-38176, ASME IGTI Conference, Atlanta, GA, June 2003.
23.
Camci, C., Kim, K., and Hippensteele, S. A., 1991, “A New Hue Capturing Technique for Quantitative Interpretation of Liquid Crystal Images Used in Convective Heat Transfer Studies,” ASME Paper 91-GT-277.
24.
Kline
,
S. J.
, and
McClintock
,
F. A.
,
1953
, “
Describing Uncertainties in Single Sample Experiments
,”
Mech. Eng. (Am. Soc. Mech. Eng.)
,
75
, pp.
3
8
.
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