This paper describes an investigation of the aerodynamic aspects of endwall film-cooling, in which the flow field downstream of a large-scale low-speed linear turbine cascade has been measured. The integrated losses and locations of secondary flow features with and without endwall film-cooling have been determined for variations of both the coolant supply pressure and injection location. Together with previous measurements of adiabatic film-cooling effectiveness and surface-flow visualization, these results reveal the nature of the interactions between the ejected coolant and the flow in the blade passage. Measured hole massflows and a constant static pressure mixing analysis, together with the measured losses, allow the decomposition of the losses into three distinct entropy generation mechanisms: loss generation within the hole, loss generation due to the mixing of the coolant with the mainstream, and change in secondary loss generation in the blade passage. Results show that the loss generation within the coolant holes is substantial and that ejection into regions of low static pressure increases the loss per unit coolant massflow. Ejection upstream of the three-dimensional separation lines on the endwall changes secondary flow and reduces its associated losses. The results show that it is necessary to take the three-dimensional nature of the endwall flow into account in the design of endwall film-cooling configurations.

1.
Bario
F.
,
Leboeuf
F.
,
Onvani
A.
, and
Seddini
A.
,
1990
, “
Aerodynamics of Cooling Jets Introduced in the Secondary Flow of a Low-Speed Turbine Cascade
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
539
546
.
2.
Biesinger, T. E., 1993, “Secondary Flow Reduction Techniques in Linear Turbine Cascades,” PhD Thesis, University of Durham; see also Biesinger, T. E., and Gregory-Smith, D. G., 1993, “Reduction in Secondary Flows and Losses in a Turbine Cascade by Upstream Boundary Layer Blowing,” ASME Paper No. 93-GT-114.
3.
Blair
M. F.
,
1974
, “
An Experimental Study of Heat Transfer and Film Cooling on Large-Scale Turbine Endwalls
,”
ASME Journal of Heat Transfer
, Vol.
96
, pp.
524
529
.
4.
Bourguignon, A. E., 1985, “Etudes des Transferts Thermiques sur les Plates-Formes de Distributeur de Turbine avec et sans Film de Refroidissement,” AGARD-CP-390, Heat Transfer and Cooling in Gas Turbines.
5.
Denton, J. D., and Cumpsty, N. A., 1987, “Loss Mechanisms in Turbomachines,” IMechE Paper No. C260/87.
6.
Friedrichs
S.
,
Hodson
H. P.
, and
Dawes
W. N.
,
1996
, “
Distribution of Film-Cooling Effectiveness on a Turbine Endwall Measured Using the Ammonia and Diazo Technique
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
118
, pp.
613
621
.
7.
Goldman, L. J., and McLallin, K. L., 1977, “Effect of Endwall Cooling on Secondary Flows in Turbine Stator Vanes,” AGARD-CPP-214.
8.
Granser, D., and Schulenberg, T., 1990, “Prediction and Measurement of Film Cooling Effectiveness for a First-Stage Turbine Vane Shroud,” ASME Paper No. 90-GT-95.
9.
Gregory-Smith
D. G.
, and
Cleak
J. G. E.
,
1992
, “
Secondary Flow Measurements in a Turbine Cascade With High Inlet Turbulence
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
114
, pp.
173
183
.
10.
Harasgama
S. P.
, and
Burton
C. D.
,
1992
, “
Film Cooling Research on the Endwall of a Turbine Nozzle Guide Vane in a Short Duration Annular Cascade: Part 1—Experimental Technique and Results
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
114
, pp.
734
741
.
11.
Harrison
S.
, 1989, “The Influence of Blade Stacking on Turbine Losses,” Ph.D. Thesis, University of Cambridge; see also Harrison, S.,
1990
, “
Secondary Loss Generation in a Linear Cascade of High-Turning Turbine Blades
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
618
624
.
12.
Hartsel, J. E., 1972, “Prediction of Effects of Mass-Transfer Cooling on the Blade-Row Efficiency of Turbine Airfoils,” AIAA Paper No. 72-11.
13.
Jabbari
M. Y.
,
Marston
K. C.
,
Eckert
E. R. G.
, and
Goldstein
R. J.
,
1996
, “
Film Cooling of the Gas Turbine Endwall by Discrete-Hole Injection
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
118
, pp.
278
284
.
14.
Leylek
J. H.
, and
Zerkle
R. D.
,
1994
, “
Discrete-Jet Film Cooling: A Comparison of Computational Results With Experiments
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
116
, pp.
358
368
.
15.
Sieverding
C. H.
,
1984
, “
Recent Progress in the Understanding of Basic Aspects of Secondary Flows in Turbine Blade Passages
,”
ASME Journal of Engineering for Gas Turbines and Power
, Vol.
107
, pp.
248
257
.
16.
Sieverding, C. H., and Wilputte, P., 1981, “Influence of Mach Number and Endwall Cooling on Secondary Flows in a Straight Nozzle Cascade,” ASME Journal of Engineering for Power, Vol. 103, No. 2.
17.
Takeishi
K.
,
Matsuura
M.
,
Aoki
S.
, and
Sato
T.
,
1990
, “
An Experimental Study of Heat Transfer and Film Cooling on Low Aspect Ratio Turbine Nozzles
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
488
496
.
18.
Wilfert
G.
, and
Fottner
L.
,
1996
, “
The Aerodynamic Mixing Effect of Discrete Cooling Jets With Mainstream Flow on a Highly Loaded Turbine Blade
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
118
, pp.
468
478
.
This content is only available via PDF.
You do not currently have access to this content.