The most recent correlations for turbine profile losses at off-design incidence include the leading-edge diameter as the only aspect of the leading-edge geometry that influences the losses. Cascade measurements are presented for two turbine blades that differ primarily in their leading-edge geometries. The incidence was varied over a range of ±20 deg and the results show significant discrepancies between the observed profile losses and those predicted by the available correlations. Using data from the present experiments, as well as cases from the literature for which sufficient geometric data are given, a revised correlation has been developed. The new correlation is a function of both the leading-edge diameter and the wedge angle, and it is significantly more successful than the existing correlations. It is argued that the off-design loss behavior of the blade is influenced by the magnitude of the discontinuity in curvature at the points where the leading-edge circle meets the rest of the blade profile. The wedge angle appears to be an approximate and convenient measure of the discontinuity in curvature at these blend points.

Issue Section:
Research Papers
Topics:
Design, Geometry, Turbines, Blades, Wedges, Cascades (Fluid dynamics), Turbine blades
1.
Ainley, D. G., and Mathieson, G. C. R., 1951, “A Method of Performance Estimation for Axial Flow Turbines,” ARC R&M 2974.
2.
Aronov
B. M.
,
Bogatyrev
A. G.
,
Epifanov
V. M.
,
Mamaev
B. I.
, and
Shkurikhin
I. B.
,
1975
, “
Experimental Study of Blade Inlet Angle Influence on Profile Cascade Effectiveness
,”
Soviet Aeronautics
, Vol.
18
, No.
3
, pp.
82
–
86
. [Data]
3.
Craig
H. R. M.
, and
Cox
H. J. A.
,
1971
, “
Performance Estimated of Axial Flow Turbines
,”
Proc. Institution of Mechanical Engineers
, Vol.
185
, No.
32
, pp.
407
–
424
.
4.
Denton
J. D.
,
1993
, “
Loss Mechanisms in Turbomachines
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
115
, pp.
621
–
656
.
5.
Dunham
J.
, and
Came
P. M.
,
1970
, “
Improvements to the Ainley/Mathieson Method of Turbine Performance Prediction
,”
ASME Journal of Engineering for Power
, Vol.
92
, pp.
252
–
256
.
6.
Goobie, S. M., Moustapha, S. H., and Sjolander, S. A., 1989, “An Experimental Investigation of the Effect of Incidence on the Two-Dimensional Performance of an Axial Turbine Cascade,” Proc. Ninth International Symposium on Air Breathing Engines, Vol. 1, pp. 197–204.
7.
Hodson
H. P.
,
1985
, “
Boundary-Layer Transition and Separation Near the Leading Edge of a High-Speed Turbine Blade
,”
ASME Journal of Engineering for Gas Turbines and Power
, Vol.
107
, pp.
127
–
134
.
8.
Hodson
H. P.
, and
Dominy
R. G.
,
1987
a, “
The Off-Design Performance of a Low-Pressure Turbine Cascade
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
109
, pp.
201
–
209
. [Data]
9.
Hodson
H. P.
, and
Dominy
R. G.
,
1987
b, “
Three-Dimensional Flow in a Low-Pressure Turbine Cascade
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
109
, pp.
177
–
185
. [Data]
10.
Kacker
S. C.
, and
Okapuu
U.
,
1982
, “
A Mean-Line Prediction Method for Axial Flow Turbine Efficiency
,”
ASME Journal of Engineering for Power
, Vol.
104
, pp.
111
–
119
.
11.
Mayle
R. E.
,
1991
, “
The Role of Laminar-Turbulent Transition in Gas Turbine Engines
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
113
, pp.
509
–
537
.
12.
Moustapha
S. H.
,
Kacker
S. C.
, and
Tremblay
B.
,
1990
, “
An Improved Incidence Losses Prediction Method for Turbine Airfoils
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
267
–
276
.
13.
Mukhtarov
M. K.
, and
Krichakin
V. I.
,
1969
, “
Procedure of Estimating Flow Section Losses in Axial Flow Turbines when Calculating their Characteristics
,”
Teploenergetika
, Vol.
16
(
7
), pp.
76
–
79
.
14.
Perdichizzi
A.
, and
Dossena
V.
,
1993
, “
Incidence Angle and Pitch-Chord Effects on Secondary Flows Downstream of a Turbine Cascade
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
115
, pp.
383
–
391
. [Data]
15.
Rodger, P., Sjolander, S. A., and Moustapha, S. H., 1992, “Establishing Two-Dimensional Flow in a Large-Scale Planar Turbine Cascade,” AIAA Paper No. 92-3066. [Data]
16.
Stow, P., 1985, “Incorporation of Viscous-Inviscid Interactions in Turbomachinery Design,” in Thermodynamics and Fluid Mechanics of Turbomachinery, A. S. Ucer, P. Stow, and Ch. Hirsch, eds., Nijhoff, Dordrecht, Vol. 2, pp. 887–921.
17.
Tremblay, B., Sjolander, S. A., and Moustapha, S. H., 1990, “Off-Design Performance of a Linear Cascade of Turbine Blades,” ASME Paper No. 90-GT-314. [Data]
18.
Vijayaraghavan, S. B., and Kavanagh, P., 1988, “Effect of Free-Stream Turbulence, Reynolds Number, and Incidence on Axial Turbine Cascade Performance,” ASME Paper No. 88-GT-152. [Data]
19.
Walraevens
R. E.
, and
Cumpsty
N. A.
,
1995
, “
Leading Edge Separation Bubbles on Turbomachinery Blades
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
117
, pp.
115
–
125
.
20.
Whitehouse
D. R.
,
Moustapha
S. H.
, and
Sjolander
S. A.
,
1993
, “
The Effect of Axial Velocity Ratio, Turbulence Intensity, Incidence, and Leading Edge Geometry on the Midspan Performance of a Turbine Cascade
,”
Canadian Aeronautics and Space Journal
, Vol.
39
, No.
3
, pp.
150
–
156
. [Data]
21.
Yamamoto
A.
, and
Nouse
H.
,
1988
, “
Effects of Incidence on Three-Dimensional Flows in a Linear Turbine Cascade
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
110
, pp.
486
–
496
. [Data]
This content is only available via PDF.
Copyright © 1997
 by The American Society of Mechanical Engineers
You do not currently have access to this content.