Improved film cooling performance and coolant flow usage have a significant effect on overall engine performance. In the current study, film cooling performance of an improved antivortex or tripod hole geometry is evaluated on a flat plate surface with steady-state IR (infrared thermography) technique and compared to traditional baseline geometry. The baseline geometry is a simple cylindrical hole design inclined at 30 deg from the surface with pitch-to-diameter ratio of 3.0. The proposed improvement is a tripod design where the two side holes, also of the same diameter, branch out from the root of the main hole at 15 deg angle with a larger pitch-to-diameter ratio of 6.0 between the main holes. The third geometry studied is the same tripod design embedded in a trench to enhance two-dimensional film performance. The mainstream Reynolds number is 3110 based on the coolant hole inlet diameter. Two secondary fluids, air and carbon dioxide, were used to study the effects of coolant-to-mainstream density ratio (DR = 0.95 and 1.45) on film cooling effectiveness. Several blowing ratios in the range 0.5–4.0 were investigated independently at the two density ratios. Results indicate significant improvement in effectiveness with the tripod holes compared to cylindrical holes at all the blowing ratios studied. The trenched design shows improved effectiveness in the trench region and reduced effectiveness in the downstream region. At any given blowing ratio, the tripod hole designs use 50% less coolant and provide at least 30%–40% overall averaged higher cooling effectiveness. The use of relatively dense secondary fluid improves effectiveness immediately downstream of the antivortex holes but leads to poor performance downstream.

References

References
1.
Goldstein
,
R. J.
,
Eckert
,
E. R. G.
, and
Burggraf
,
F.
,
1973
, “
Effects of Hole Geometry and Density on Three-Dimensional Film Cooling
,”
Int. J. Heat Mass Transfer
,
17
, pp.
595
607
.10.1016/0017-9310(74)90007-6
2.
Pedersen
,
D. R.
,
Eckert
,
E. R. G.
, and
Goldstein
,
R. J.
,
1977
, “
Film Cooling With Large Density Differences Between Mainstream and the Secondary Fluid Measured by the Heat-Mass Transfer Analogy
,”
ASME J. Heat Transfer
,
99
, pp.
620
627
.10.1115/1.3450752
3.
Sinha
,
A. K.
,
Bogard
,
D. G.
, and
Crawford
,
M. E.
,
1991
, “
Film- Cooling Effectiveness Downstream of a Single Row of Holes With Variable Density Ratio
,”
ASME J. Turbomach.
,
113
, pp.
442
449
.10.1115/1.2927894
4.
Ligrani
,
P. M.
,
Wigle
,
J. M.
,
Ciriello
,
S.
, and
Jackson
,
S. W.
,
1994(a)
, “
Film-Cooling From Holes With Compound Angle Orientations: Part 1—Results Downstream of Two Staggered Row of Holes With 3D Spanwise Spacing
,”
ASME J. Heat Transfer
,
116
, pp.
341
352
.10.1115/1.2911406
5.
Schmidt
,
D. L.
,
Sen
,
B.
, and
Bogard
,
D. G.
,
1994
, “
Film Cooling With Compound Angle Holes: Adiabatic Effectiveness
,”
IGTI Turbo Expo
,
The Hague, Netherlands
, ASME Paper No. 94-GT-312.
6.
Leylek
,
J. H.
, and
Zerkle
,
R. D.
,
1994
, “
Discrete-Jet Film Cooling: A Comparison of Computational Results With Experiments
,”
ASME J. Turbomach.
,
116
, pp.
358
368
.10.1115/1.2929422
7.
Gritsch
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
,
1997
, “
Adiabatic Wall Effectiveness Measurements of Film-Cooling Holes With Expanded Exits
,”
IGTI Conference
,
Orlando
, ASME Paper No. 97-GT-164.
8.
Han
,
J. C.
,
Dutta
,
S.
, and
Ekkad
,
S.
,
2000
,
Gas Turbine Heat Transfer and Cooling Technology
,
Taylor and Francis
,
New York
.
9.
Bunker
,
R. S.
,
2005
, “
A Review of Shaped Hole Turbine Film-Cooling Technology
,”
ASME J. Heat Transf.
,
127
, pp.
441
453
.10.1115/1.1860562
10.
Shih
,
T. I.-P.
,
Lin
,
Y.-L.
,
Chyu
,
M. K.
, and
Gogineni
,
S.
,
1999
, “
Computations of Film Cooling From Holes With Struts
,” ASME Paper No. 99–GT–282.
11.
Papell
,
S. S.
,
1984
, “
Vortex Generating Flow Passage Design for Increased Film-Cooling Effectiveness and Surface Coverage
,”
22nd National Heat Transfer Conference
,
Niagara Falls, NY
, August 5–8.
12.
Zaman
,
K. B. M. Q.
, and
Foss
,
J. K.
,
1997
, “
The Effects of Vortex Generators on a Jet in Crossflow
,”
Phys. Fluids
,
9
, pp.
106
114
.10.1063/1.869154
13.
Bunker
,
R. S.
,
2002
, “
Film Cooling Effectiveness Due to Discrete Holes Within a Transverse Surface Slot
,”
ASME
Paper No. GT2002-30178.10.1115/GT2002-30178
14.
Lu
,
Y.
,
Faucheaux
,
D.
, and
Ekkad
,
S. V.
,
2005
, “
Film Cooling Measurements for Novel Hole Configurations
,”
ASME
Paper No. HT2005-72396.10.1115/HT2005-72396
15.
Kusterer
,
K.
,
Bohn
,
D.
,
Sugimoto
,
T.
, and
Tanaka
,
R.
,
2007
, “
Double-Jet Ejection of Cooling Air for Improved Film Cooling
,”
ASME J. Turbomach.
,
129
, pp.
809
815
.10.1115/1.2720508
16.
Liu
,
J. S.
,
Malak
,
M. F.
,
Tapia
,
L. A.
,
Crites
,
D. C.
,
Ramachandran
,
D.
,
Srinivasan
,
B.
,
Muthiah
,
G.
, and
Venkataramanan
,
J.
, 2010, “
Enhanced Film Cooling Effectiveness With New Shaped Holes
,”
ASME
Paper No. GT2010-22774.10.1115/GT2010-22774
17.
Heidmann
,
J. D.
, and
Ekkad
,
S. V.
,
2008
, “
A Novel Antivortex Turbine Film-Cooling Hole Concept
,”
ASME J. Turbomach.
,
130
(
3
), p.
031020
.10.1115/1.2777194
18.
Dhungel
,
S.
,
Lu
,
Y.
,
Phillips
,
W.
,
Ekkad
,
S. V.
, and
Heidmann
,
J. D.
,
2009
, “
Film Cooling From a Row of Holes Supplemented With Antivortex Holes
,”
ASME J. Turbomach.
,
131
(2), p. 021007.10.1115/1.2950059
19.
Coleman
,
H. W.
, and
Steele
,
W. G.
,
1989
,
Experimentation and Uncertainty Analysis for Engineers
,
John Wiley & Sons
,
New York
, Chaps. 3–4.
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