The physical characteristics of surface roughness observed on first-stage high-pressure turbine vanes that had been in service for a long period were investigated in this study. Profilometry measurements were utilized to provide details of the surface roughness formed by deposits of foreign materials on different parts of the turbine vane. Typical measures of surface roughness such as centerline average roughness values were shown to be inadequate for characterizing roughness effects. Using a roughness shape parameter originally derived from regular roughness arrays, the turbine airfoil roughness was characterized in terms of equivalent sand-grain roughness in order to develop an appropriate simulation of the surface for laboratory experiments. Two rough surface test plates were designed and fabricated. These test plates were evaluated experimentally to quantify the heat transfer rate for flow conditions similar to that which occurs on the turbine airfoil. Although the roughness levels on the two test plates were different by a factor of two, both surfaces caused similar 50 percent increases in heat transfer rates relative to a smooth surface. The effects of high free-stream turbulence, with turbulence levels from 10 to 17 percent, were also investigated. Combined free-stream turbulence and surface roughness effects were found to be additive, resulting in as much as a 100 percent increase in heat transfer rate.

1.
Acharya
M.
,
Bornstein
J.
, and
Escudier
M. P.
,
1986
, “
Turbulent Boundary Layers on Rough Surfaces
,”
Exper. In Fluids
, Vol.
4
, pp.
33
47
.
2.
Bammert
K.
, and
Sanstede
H.
,
1972
, “
Measurements Concerning the Influence of Surface Roughness and Profile Changes on the Performance of Gas Turbine Engines
,”
ASME Journal of Engineering for Power
, Vol.
94
, pp.
207
213
.
3.
Bammert
K.
, and
Sanstede
H.
,
1976
, “
Influences of Manufacturing Tolerances and Surface Roughness of Blades on the Performance of Turbines
,”
ASME Journal of Engineering for Power
, Vol.
98
, pp.
29
36
.
4.
Blair
M. F.
,
1994
, “
An Experimental Study of Heat Transfer in a Large-Scale Turbine Rotor Passage
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
116
, pp.
1
13
.
5.
Colebrook
C. F.
, and
White
C. M.
,
1937
, “
Experiments With Fluid Friction in Roughened Pipes
,”
Proc. Royal Society of London
, Vol.
161
, pp.
367
381
.
6.
Coleman
H. W.
,
Hodge
B. K.
, and
Taylor
R. P.
,
1984
, “
A Re-evaluation of Schlichting’s Surface Experiment
,”
ASME Journal of Fluids Engineering
, Vol.
106
, pp.
60
65
.
7.
Forster, V. T., 1967, “Performance Loss of Modern Steam-Turbine Plant Due to Surface Roughness,” Proc. Instn. Mech. Engrs. 1966–67, Vol. 181, Pt. 1, pp. 391–405.
8.
Hosni
M. H.
,
Coleman
H. W.
, and
Taylor
R. P.
,
1991
, “
Measurements and Calculations of Rough-Wall Heat Transfer in the Turbulent Boundary Layer
,”
International Journal of Heat and Mass Transfer
, Vol.
34
, No.
4
, pp.
1067
1082
.
9.
Kays, W. M., and Crawford, M. E., 1993, Convective Heat and Mass Transfer, 3rd ed., McGraw-Hill, New York.
10.
Koch
C. C.
, and
Smith
L. H.
,
1976
, “
Loss Sources and Magnitudes in Axial-Flow Compressors
,”
ASME Journal of Engineering for Power
, Vol.
98
, pp.
411
424
.
11.
Nikuradse
J.
,
1933
, “
Laws for Flow in Rough Pipes
,”
VDI-Forschungsheft
, Series B, Vol.
4
, pp.
361
361
.
12.
Pietrzyk
J. R.
,
Bogard
D. G.
, and
Crawford
M. E.
,
1990
, “
Effect of Density Ratio on the Hydrodynamics of Film Cooling
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
437
443
.
13.
Pimenta, M. M., Moffat, R. J., and Kays, W. M., 1975, “The Turbulent Boundary Layer: An Experimental Study of the Transport of Momentum and Heat With the Effect of Roughness,” Thermoscience Division, Department of Mechanical Engineering, Stanford University, Report HMT-21.
14.
Schlichting, H., 1979, Boundary Layer Theory, 7th ed. McGraw-Hill, New York.
15.
Sigal
A.
, and
Danberg
J. E.
,
1990
, “
New Correlation of Roughness Density Effects on the Turbulent Boundary Layer
,”
AIAA Journal
, Vol.
28
, pp.
554
556
.
16.
Speidel
L.
,
1954
, “
Influence of the Surface Roughness on the Flow Losses in Plane Blade Cascades
,”
Forsch. Ing.-Wes.
, Vol.
20
, No.
5
, pp.
129
140
.
17.
Tarada, F., and Suzuki, M., 1993, “External Heat Transfer Enhancement to Turbine Blading Due to Surface Roughness,” ASME Paper 93-GT-74.
18.
Taylor
R. P.
,
1990
, “
Surface Roughness Measurements on Gas Turbine Blades
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
112
, pp.
175
180
.
19.
Thole
K. A.
, and
Bogard
D. G.
,
1995
, “
Enhanced Heat Transfer and Shear Stress Due to High Free-Stream Turbulence
,”
ASME JOURNAL OF TURBOMACHINERY
, Vol.
117
, pp.
418
424
.
20.
Thole
K. A.
,
Bogard
D. G.
, and
Whan-Tong
J.
,
1994
, “
Generating High Freestream Turbulence Levels
,”
Exper. in Fluids
, Vol.
17
, pp.
375
380
.
21.
White, F. M., 1974, Viscous Fluid Flow, McGraw-Hill, New York.
This content is only available via PDF.
You do not currently have access to this content.