Film cooling in gas turbines leads to aerodynamic mixing losses and reduced temperatures of the gas flow. Improvements of the gas turbine thermal efficiency can be achieved by reducing the cooling fluid amount and by establishing a more equal distribution of the cooling fluid along the surface. It is well known that vortex systems in the cooling jets are the origin of reduced film-cooling effectiveness. For the streamwise ejection case, kidney vortices result in a liftoff of the cooling jets; for the lateral ejection case, usually only one dominating vortex remains, leading to hot gas flow underneath the jet from one side. Based on the results of numerical analyses, a new cooling technology has been introduced by the authors, which reaches high film-cooling effectiveness as a result of a well-designed cooling hole arrangement for interaction of two neighboring cooling jets (double-jet film cooling (DJFC)). The results show that configurations exist, where an improved film-cooling effectiveness can be reached because an anti-kidney vortex pair is established in the double-jet. The paper aims at the following major contributions: (1) to introduce the DJFC as an alternative film-cooling technology to conventional film-cooling design; (2) to explain the major phenomena, which leads to the improvement of the film-cooling effectiveness by application of the DJFC; and (3) to prove basic applicability of the DJFC to a realistic blade cooling configuration and present the first test results under machine operating conditions.

1.
Bergeles
,
G.
,
Gosman
,
A. D.
, and
Launder
,
A. D.
, 1976, “
The Prediction of Three-dimensional Discrete-hole Cooling Processes
,”
J. Heat Transfer
0022-1481,
98
, pp.
379
386
.
2.
Leylek
,
J. H.
, and
Zerkle
,
R. D.
, 1994, “
Discrete-Jet Film Cooling: A Comparison of Computational Results with Experiments
,”
ASME J. Turbomach.
0889-504X,
116
, pp.
358
368
.
3.
Walters
,
D. K.
, and
Leylek
,
J. H.
, 2000, “
A Detailed Analysis of Film-Cooling Physics Part I: Streamwise Injection with Cylindrical Holes
,”
ASME J. Turbomach.
0889-504X,
122
, pp.
102
112
.
4.
Hall
,
J. E.
,
Topp
,
D. A.
, and
Delaney
,
R. A.
, 1994, “
Aerodymamic/Heat Transfer Analysis of Discrete Site Film-cooled Turbine Airfoils
,” AIAA Paper No. 94–3070.
5.
Bohn
,
D.
, and
Kusterer
,
K.
, 1999, “
Blowing Ratio Influence on Jet Mixing Flow Phenomena at the Leading Edge
,” AIAA Paper No. 99–0670.
6.
Lee
,
S. W.
,
Kim
,
Y. B.
, and
Lee
,
J. S.
, 1995, “
Flow Characteristics and Aerodynamic Losses of Film-cooling Jets with Compound Angle Orientations
,” ASME Paper No. 95-GT-38.
7.
McGovern
,
K. T.
, and
Leylek
,
J. H.
, 2000, “
A Detailed Analysis of Film Cooling Physics Part II. Compound-Angle Injection with Cylindrical Holes
,”
ASME J. Turbomach.
0889-504X,
122
, pp.
113
121
.
8.
Baier
,
R.-D.
,
Broichhausen
,
K.-D.
,
Koschel
,
W.
, and
Parvizinia
,
M.
, 1997, “
Numerical and Experimental Study on the Influence of Angle Orientations on the Behaviour of Discrete Film Cooling Holes on Turbine Bladings
,”
Proceedings International Symposium on Airbreathing Engines
, ISABE Paper No. 97–7109, Chattanooga, TN, Sept. 7–12, 1997.
9.
York
,
D. Y.
, and
Leylek
,
J. H.
, 2002, “
Leading-Edge Film-Cooling Physics: Part I—Adiabatic Effectiveness
,” ASME Paper No. GT-2002-30166.
10.
York
,
D. Y.
and
Leylek
,
J. H.
, 2002, “
Leading-Edge Film-Cooling Physics: Part II—Heat Transfer Coefficient
,” ASME Paper No. GT-2002-30167.
11.
Goldstein
,
R. J.
, and
Jin
,
P.
, 2000, “
Film Cooling Downstream of a Row of Discrete Holes with Compound Angle
,” ASME Paper No. 2000-GT-248.
12.
Bohn
,
D.
, and
Kusterer
,
K.
, 2000, “
Aerothermal Investigations of Mixing Flow Phenomena in Case of Radially Inclined Ejection Holes at the Leading Edge
,”
ASME J. Turbomach.
0889-504X,
122
, pp.
334
339
.
13.
Ardey
,
S.
, 1998, “
3D-Messung des Strömungsfeldes um die filmgekühlte Vorderkante einer Referenzschaufel
,” Ph.D. thesis, University of the Armed Forces, Munich, Germany (in German).
14.
Goldstein
,
R. J.
,
Eckert
,
E. R. G.
, and
Burggraf
,
F.
, 1974, “
Effects of Hole Geometry and Density on Three-Dimensional Film Cooling
,”
Int. J. Heat Mass Transfer
0017-9310,
17
, pp.
595
607
.
15.
Gritsch
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
, 1998, “
Adiabatic Wall Measurements of Film-Cooling Holes with Expanded Exits
,”
ASME J. Turbomach.
0889-504X,
120
, pp.
568
574
.
16.
Lutum
,
E.
, von
Wolfersdorf
,
J.
,
Semmler
,
K.
,
Dittmar
,
J.
, and
Weigand
,
B.
, 2001, “
An Experimental Investigation of Film Cooling on a Convex Surface Subjected to Favourable Pressure Gradient Flow
,”
Int. J. Heat Mass Transfer
0017-9310,
45
, pp.
939
951
.
17.
Yuen
,
C. H. N.
,
Martinez-Botas
,
R. F.
, and
Whitelaw
,
J. H.
, 2001, “
Film Cooling Effectiveness Downstream of Compound and Fan-shaped Holes
,” ASME Paper No. 2001-GT-0131.
18.
Saumweber
,
C.
, and
Schulz
,
A.
, 2003, “
Interaction of Film Cooling Rows: Effects of Hole Geometry and Row Spacing on the Cooling Performance Downstream of the Second Row of Holes
,” ASME Paper No. GT-2003-38195.
19.
Bohn
,
D.
,
Ren
,
J.
, and
Kusterer
,
K.
, 2003, “
Conjugate Heat Transfer Analysis for Film Cooling Configurations with Different Hole Geometries
,” ASME Paper No. GT-2003-38369.
20.
Martin
,
C. A.
, and
Thole
,
K. A.
, 1997, “
A CFD Benchmark Study: Leading Edge Film-cooling with Compound Angle Injection
,” ASME Paper No. 97-GT-297.
21.
Martelli
,
F.
,
Adami
,
P.
, and
Belardini
,
E.
, 2001, “
Numerical Investigation of Heat Transfer and Film Cooling for Gas Turbine Application
,”
Proceedings International Symposium on Airbreathing Engines
, ISABE Paper No. 2001-1102, Bangalore, India, Sept. 2–7, 2001.
22.
Bohn
,
D.
,
Becker
,
V.
,
Kusterer
,
K.
,
Fottner
,
L.
, and
Ardey
,
S.
, 2000, “
Three-Dimensional Flow Analysis of Turbine Blade Cascades with Leading Edge Ejection
,”
J. Propul. Power
0748-4658,
16
, pp.
49
56
.
23.
Heidmann
,
J. D.
,
Rigby
,
D. L.
, and
Ameri
,
A. A.
, 2000, “
A Three-Dimensional Coupled Internal/External Simulation of a Film-cooled Turbine Vane
,”
ASME J. Turbomach.
0889-504X,
122
, pp.
348
359
.
24.
Vogel
,
D. T.
, 1998, “
Numerical Investigation of the Influence of Specific Vortex Generation on the Mixing Process of Film Cooling Jets
,” ASME Paper No. 98-GT-210.
25.
Haven
,
B. A.
,
Yamagata
,
D. K.
,
Kurosaka
,
M.
,
Yamawaki
,
S.
, and
Maya
,
T.
, 1997, “
Anti-Kidney Pair of Vortices in Shaped Holes and their Influence on Film Cooling Effectiveness
,” ASME Paper No. 97-GT-45.
26.
Japanese Patent Application No. 332530, “
Double Jet Film Cooling Structure
,” 2005.
27.
Bohn
,
D.
,
Krüger
,
U.
, and
Kusterer
,
K.
, 2001, “
Conjugate Heat Transfer: An Advanced Computational Method for the Cooling Design of Modern Gas Turbine Blades and Vanes
,”
Heat Transfer in Gas Turbines
,
B.
Sundén
and
M.
Faghri
, eds.,
WIT Press
,
Southampton, UK
, pp.
58
108
.
28.
Baldwin
,
B. S.
, and
Lomax
,
H.
, 1978, “
Thin Layer Approximation and Algebraic Model for Separated Turbulent Flows
,” AIAA Paper No. 78–257.
You do not currently have access to this content.