Heat transfer distributions are experimentally acquired and reported for a vane with both a smooth and a realistically rough surface. Surface heat transfer is investigated over a range of turbulence levels (low (0.7%), grid (8.5%), aerocombustor (13.5%), and aerocombustor with decay (9.5%)) and a range of chord Reynolds numbers ($ReC=500,000$, 1,000,000, and 2,000,000). The realistically rough surface distribution was generated by Brigham Young University’s accelerated deposition facility. The surface is intended to represent a TBC surface that has accumulated 7500 h of operation with particulate deposition due to a mainstream concentration of 0.02 ppmw. The realistically rough surface was scaled by 11 times for consistency with the vane geometry and cast using a high thermal conductivity epoxy $(k=2.1 W/m/K)$ to comply with the vane geometry. The surface was applied over the foil heater covering the vane pressure surface and about 10% of the suction surface. The $958×573$ roughness array generated by Brigham Young on a $9.5×5.7 mm2$ region was averaged to a $320×191$ array for fabrication. The calculated surface roughness parameters of this scaled and averaged array included the maximum roughness, $Rt=1.99 mm$, the average roughness, $Ra=0.25 mm$, and the average forward facing angle, $αf=3.974 deg$. The peak to valley roughness, Rz, was determined to be 0.784 mm. The sand grain roughness of the surface $(kS=0.466 mm)$ was estimated using a correlation offered by Bons (2005, “A Critical Assessment of Reynolds Analogy for Turbine Flows,” ASME J. Turbomach., 127, pp. 472–485). Based on estimates of skin friction coefficient using a turbulence correlation with the vane chord Reynolds numbers representative values for the surface’s roughness Reynolds number are 23, 43, and 80 for the three exit condition Reynolds numbers tested. Smooth vane heat transfer distributions exhibited significant laminar region augmentation with the elevated turbulence levels. Turbulence also caused early transition on the pressure surface for the higher Reynolds numbers. The rough surface had no significant effect on heat transfer in the laminar regions but caused early transition on the pressure surface in every case.

1.
Erickson
,
E.
,
Ames
,
F. E.
, and
Bons
,
J. P.
, 2010, “
Effects of a Realistically Rough Surface on Vane Aerodynamic Losses Including the Influence of Turbulence Condition and Reynolds Number
,”
ASME
Paper No. GT2010-22173.
2.
Bons
,
J. P.
, 2009, “
A Review of Surface Roughness Effects in Gas Turbines
,”
ASME J. Turbomach.
0889-504X,
131
, p.
004902
.
3.
Bons
,
J. P.
,
Taylor
,
R. P.
,
McClain
,
S. T.
, and
Rivir
,
R. B.
, 2001, “
The Many Faces of Turbine Surface Roughness
,”
ASME J. Turbomach.
0889-504X,
123
, pp.
739
748
.
4.
Wammack
,
J. E.
,
Crosby
,
J.
,
Fletcher
,
D.
,
Bons
,
J. P.
, and
Fletcher
,
T. H.
, 2008, “
Evolution of Surface Deposits on a High-Pressure Turbine Blade-Part I: Physical Characteristics
,”
ASME J. Turbomach.
0889-504X,
130
, p.
021020
.
5.
Bons
,
J. P.
, and
McClain
,
S. T.
, 2004, “
The Effect of Real Turbine Roughness With Pressure Gradient on Heat Transfer
,”
ASME J. Turbomach.
0889-504X,
126
, pp.
385
394
.
6.
Bons
,
J. P.
,
Wammack
,
J. E.
,
Crosby
,
J.
,
Fletcher
,
D.
, and
Fletcher
,
T. H.
, 2008, “
Evolution of Surface Deposits on a High-Pressure Turbine Blade-Part II: Convective Heat Transfer
,”
ASME J. Turbomach.
0889-504X,
130
, p.
021021
.
7.
Bons
,
J. P.
, 2002, “
St and Cf Augmentation for Real Turbine Roughness With Elevated Freestream Turbulence
,”
ASME J. Turbomach.
0889-504X,
124
, pp.
632
644
.
8.
Bons
,
J. P.
, 2005, “
A Critical Assessment of Reynolds Analogy for Turbine Flows
,”
ASME J. Turbomach.
0889-504X,
127
, pp.
472
485
.
9.
McIlroy
,
H. M.
, and
Budwig
,
R. S.
, 2007, “
The Boundary Layer Over Turbine Blade Models With Realistic Rough Surfaces
,”
ASME J. Turbomach.
0889-504X,
129
, pp.
318
330
.
10.
Bunker
,
R. S.
, 1997, “
Separate and Combined Effects of Surface Roughness and Turbulence Intensity on Vane Heat Transfer
,”
ASME
Paper No. 97-GT-135.
11.
Stripf
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
, 2005, “
Surface Roughness Effects on External Heat Transfer of a HP Turbine Vane
,”
ASME J. Turbomach.
0889-504X,
127
, pp.
200
208
.
12.
Dees
,
J. S.
, and
Bogard
,
D. G.
, 2008, “
Effects of Regular and Random Roughness on Heat Transfer and Skin Friction Coefficient on the Suction Side of a Gas Turbine Vane
,”
ASME J. Turbomach.
0889-504X,
130
, p.
041012
.
13.
Rutledge
,
J. L.
,
Robertson
,
D.
, and
Bogard
,
D. G.
, 2006, “
Degradation of Film Cooling Performance on a Turbine Vane Suction Surface Due to Surface Roughness
,”
ASME J. Turbomach.
0889-504X,
128
, pp.
547
554
.
14.
Ames
,
F. E.
,
Wang
,
C.
, and
Barbot
,
P. A.
, 2003, “
Measurement and Prediction of the Influence of Catalytic and Dry Low NOx Combustor Turbulence on Vane Surface Heat Transfer
,”
ASME J. Turbomach.
0889-504X,
125
, pp.
221
231
.
15.
Fiala
,
N. J.
,
Jaswal
,
I.
, and
Ames
,
F. E.
, 2010, “
Letterbox Trailing Edge Heat Transfer–Effects of Blowing Rate, Reynolds Number, and External Turbulence on Heat Transfer and Film Cooling Effectiveness
,”
ASME J. Turbomach.
0889-504X,
132
, p.
011017
.
16.
FLUENT 6.3, 2006, FLUENT 6.3 User’s Guide, Fluent, Inc., Lebanon, N. H.
17.
Ames
,
F. E.
,
Argenziano
,
M.
, and
Wang
,
C.
, 2004, “
Measurement and Prediction of Heat Transfer Distributions on an Aft Loaded Vane Subjected to the Influence of Catalytic and Dry Low NOx Combustor Turbulence
,”
ASME J. Turbomach.
0889-504X,
126
, pp.
139
149
.
18.
Moffat
,
R. J.
, 1988, “
Describing Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
0894-1777,
1
, pp.
3
17
.
19.
Kays
,
W. M.
, 1987, “
STAN7, A Finite Difference Boundary Layer Code
.”
20.
Ames
,
F. E.
,
Kwon
,
K.
, and
Moffat
,
R. J.
, 1999, “
An Algebraic Model for High Intensity Large Scale Turbulence
,”
ASME
Paper No. 99-GT-160.
21.
Mayle
,
R. E.
, 1991, “
The Role of Laminar-Turbulent Transition in Gas Turbine Engines
,”
ASME J. Turbomach.
0889-504X,
113
, pp.
509
537
.
22.
Boyle
,
R. J.
, and
Senyitko
,
R. G.
, 2003, “
Measurements and Predictions of Surface Roughness Effects on Turbine Vane Aerodynamics
,”
ASME
Paper No. GT2003-38580.
You do not currently have access to this content.