Durability of turbine blade tips has been and continues to be challenging, particularly since increasing turbine inlet temperatures is the driver for improving turbine engine performance. As a result, cooling methods along the blade tip are crucial. Film-cooling is one typically used cooling method whereby coolant is supplied through holes placed along the pressure side of a blade. The subject of this paper is to evaluate the adiabatic effectiveness levels that occur on the blade tip through blowing coolant from holes placed near the tip of a blade along the pressure side. A range of blowing ratios was studied whereby coolant was injected from holes placed along the pressure side tip of a large-scale blade model. Also present were dirt purge holes on the blade tip, which is part of a commonly used blade design to expel any large particles present in the coolant stream. Experiments were conducted in a linear cascade with a scaled-up turbine blade whereby the Reynolds number of the engine was matched. This paper, which is Part 1 of a two part series, compares adiabatic effectiveness levels measured along a blade tip, while Part 2 combines measured heat transfer coefficients with the adiabatic effectiveness levels to assess the overall cooling benefit of pressure side blowing near a blade tip. The results show much better cooling can be achieved for a small tip gap compared with a large tip gap with different flow phenomena occurring for each tip gap setting.

1.
Christophel
,
J.
,
Thole
,
K. A.
, and
Cunha
,
F.
,
2005
, “
Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part II: Heat Transfer Measurements
,”
ASME J. Turbomach.
127
, pp.
278
286
.
2.
Bunker, R. S., 2000, “A Review of Turbine Blade Tip Heat Transfer,” Turbine 2000 Symposium on Heat Transfer in Gas Turbine Systems, Cesme, Turkey.
3.
Kim
,
Y. W.
, and
Metzger
,
D. E.
,
1995
, “
Heat Transfer and Effectiveness on Film Cooled Turbine Blade Tip Models
,”
ASME J. Turbomach.
,
117
, pp.
12
21
.
4.
Kim
,
Y. W.
,
Downs
,
J. P.
,
Soechting
,
F. O.
,
Abdel-Messeh
,
W.
,
Steuber
,
G.
, and
Tanrikut
,
S.
,
1995
, “
A Summary of the Cooled Turbine Blade Tip Heat Transfer and Film Effectiveness Investigations Performed by Dr. D. E. Metzger
,”
ASME J. Turbomach.
,
117
, pp.
1
11
.
5.
Kwak, J. S., and Han, J. C., 2002, “Heat Transfer Coefficient and Film-Cooling Effectiveness on a Gas Turbine Blade Tip,” GT2002-30194.
6.
Kwak, J. S., and Han, J. C., 2002, “Heat Transfer Coefficient and Film-Cooling Effectiveness on the Squealer Tip of a Gas Turbine Blade,” GT2002-30555.
7.
Acharya, S., Yang, H., Ekkad, S. V., Prakash, C., and Bunker, R., 2002, “Numerical Simulation of Film Cooling Holes on the Tip of a Gas Turbine Blade,” GT-2002-30553.
8.
Hohlfeld, E. M., Christophel, J. R., Couch, E. L., and Thole, K. A., 2003, “Predictions of Cooling From Dirt Purge Holes Along the Tip of a Turbine Blade,” GT2003-38251.
9.
Srinivasan
,
V.
, and
Goldstein
,
R. J.
,
2003
, “
Effect of Endwall Motion on Blade Tip Heat Transfer
,”
ASME J. Turbomach.
,
125
, pp.
267
273
.
10.
Ameri, A. A., 2001, “Heat Transfer and Flow on the Blade Tip of a Gas Turbine Equipped With a Mean-Camberline Strip,” 2001-GT-0156.
11.
Moffat
,
R. J.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
,
1
, pp.
3
17
.
12.
Fluent Inc., Fluent User’s Guide, Version 6.0, 2002 (Fluent Inc., New Hampshire).
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