Abstract

Convective cooling in a gas turbine blade internal trailing edge channel is often insufficient at the sharp trailing edge. This study examines convective heat transfer and pressure drop within a simplified nonrotating trailing edge channel. The internal passage has been modeled as a right triangular channel with a 9 deg angle sharp corner. A copper plate was heated from underneath via a uniform heat flux heater and examined via infrared thermography for two cases: smooth wall and single-sided ribbed wall. Nonuniformity in the heat flux due to conduction is corrected by a Reynolds-averaged Navier–Stokes (RANS) conjugate heat transfer calculation, which was validated by the mean velocity, friction factor, and temperature fields from experiments and large eddy simulation (LES). Nusselt number distributions illustrate that surface heat transfer is increased considerably with ribs and coupled with the vortices in the flow. Heat transfer at the sharp corner is increased by more than twofold due to ribs placed at the center of the channel due to secondary flow. The present single-sided ribbed channel utilizes secondary flow toward the corner and is presumed to have better thermal performance than a dual-sided ribbed channel. Thus, it is important to set the appropriate rib length within the channel.

References

1.
Naik
,
S.
,
Retzko
,
S.
,
Gritsch
,
M.
, and
Sedlov
,
A.
,
2014
, “
Impact of Turbulator Design on the Heat Transfer in a High Aspect Ratio Passage of a Turbine Blade
,”
Proceedings ASME Turbo Expo 2014
,
Düsseldorf, Germany
, Paper No. GT2014-25841.
2.
Han
,
J. C.
,
2004
, “
Recent Studies in Turbine Blade Cooling
,”
Int. J. Rotating Mach.
,
10
(
6
), pp.
443
457
.
3.
Cunha
,
F.
, and
Chyu
,
M. K.
,
2006
, “
Trailing Edge Cooling for Gas Turbines
,”
J. Propuls. Power
,
22
(
2
), pp.
286
300
.
4.
Horbach
,
T.
,
Schulz
,
A.
, and
Bauer
,
H. J.
,
2011
, “
Trailing Edge Film Cooling of Gas Turbine Airfoils—External Cooling Performance of Various Internal Pin Fin Configurations
,”
ASME J. Turbomach.
,
133
(
4
), p.
041006
.
5.
Martini
,
P.
,
Schulz
,
A.
, and
Bauer
,
H. J.
,
2006
, “
Film Cooling Effectiveness and Heat Transfer on the Trailing Edge Cutback of Gas Turbine Airfoils With Various Internal Cooling Designs
,”
ASME J. Turbomach.
,
128
(
1
), pp.
196
205
.
6.
Martini
,
P.
,
Schulz
,
A.
,
Bauer
,
H. J.
, and
Whitney
,
C. F.
,
2006
, “
Detached Eddy Simulation of Film Cooling Performance on the Trailing Edge Cutback of Gas Turbine Airfoils
,”
ASME J. Turbomach.
,
128
(
2
), pp.
292
299
.
7.
Schneider
,
H.
,
von Terzi
,
D.
, and
Bauer
,
H. J.
,
2010
, “
Large Eddy Simulations of Trailing Edge Cutback Film Cooling at Low Blowing Ratio
,”
Int. J. Heat Fluid Flow
,
31
(
5
), pp.
767
775
.
8.
Saxer-Felici
,
H.
,
Naik
,
S.
, and
Gritsch
,
M.
,
2013
, “
Heat Transfer Characteristics of a Blade Trailing Edge With Pressure Side Bleed Extraction
,”
Proceedings ASME Turbo Expo 2013
,
San Antonio, TX
, Paper No. GT2013-95003.
9.
Coletti
,
F.
,
Scialanga
,
M.
, and
Arts
,
T.
,
2012
, “
Experimental Investigation of Conjugate Heat Transfer in a Rib Roughened Trailing Edge Channel With Crossing Jets
,”
ASME J. Turbomach.
,
134
(
4
), p.
041016
.
10.
Ahn
,
J.
,
Choi
,
H.
, and
Lee
,
J. S.
,
2005
, “
Large Eddy Simulation of Flow and Heat Transfer in a Channel Roughened by Square or Semicircle Ribs
,”
ASME J. Turbomach.
,
127
(
2
), pp.
263
292
.
11.
Astarita
,
T.
, and
Cardone
,
G.
,
2003
, “
Convective Heat Transfer in a Square Channel With Angled Ribs on Two Opposite Walls
,”
Exp. Fluids
,
34
(
5
), pp.
625
634
.
12.
Tanda
,
G.
,
2011
, “
Effect of Rib Spacing on Heat Transfer and Friction in a Rectangular Channel With 45° Angled Rib Turbulators on One/Two Walls
,”
Int. J. Heat Mass Transfer
,
54
(
5–6
), pp.
1081
1090
.
13.
Peng
,
W.
,
Jiang
,
P. X.
,
Wang
,
Y. P.
, and
Wei
,
B. Y.
,
2011
, “
Experimental and Numerical Investigation of Convection Heat Transfer in Channels With Different Types of Ribs
,”
Appl. Therm. Eng.
,
31
(
14–15
), pp.
2702
2708
.
14.
SriHarsha
,
V.
,
Prabhu
,
S.
, and
Vedula
,
R.
,
2009
, “
Influence of Rib Height on the Local Heat Transfer Distribution and Pressure Drop in a Square Channel With 90° Continuous and 60° V-Broken Ribs
,”
Appl. Therm. Eng.
,
29
(
11–12
), pp.
2444
2459
.
15.
Rallabandi
,
A. P.
,
Yang
,
H.
, and
Han
,
J. C.
,
2009
, “
Heat Transfer and Pressure Drop Correlations for Square Channels With 45 deg Ribs at High Reynolds Numbers
,”
ASME J. Heat Transfer-Trans. ASME
,
131
(
7
), p.
071703
.
16.
Alkhamis
,
N. Y.
,
Rallabandi
,
A. P.
, and
Han
,
J. C.
,
2011
, “
Heat Transfer and Pressure Drop Correlations for Square Channels With V-Shaped Ribs at High Reynolds Numbers
,”
ASME J. Heat Transfer-Trans. ASME
,
133
(
11
), p.
111901
.
17.
Won
,
S.
,
Burgess
,
N.
,
Peddicord
,
S.
, and
Ligrani
,
P.
,
2004
, “
Spatially Resolved Surface Heat Transfer for Parallel Rib Turbulators With 45 deg Orientations Including Test Surface Conduction Analysis
,”
ASME J. Heat Transfer
,
126
(
2
), pp.
193
201
.
18.
Eckert
,
E. R. G.
, and
Irvine
,
T.
,
1960
, “
Pressure Drop and Heat Transfer in a Duct With Triangular Cross Section
,”
ASME J. Heat Transfer-Trans. ASME
,
82
(
2
), pp.
125
138
.
19.
Leung
,
C. W.
,
Wong
,
T. T.
, and
Kang
,
H. J.
,
1998
, “
Forced Convection of Turbulent Flow in Triangular Ducts With Different Angles and Surface Roughnesses
,”
Heat Mass Transfer
,
34
(
1
), pp.
63
68
.
20.
Carlson
,
L.
, and
Irvine
,
T.
,
1961
, “
Fully Developed Pressure Drop in Triangular Shaped Ducts
,”
ASME J. Heat Transfer-Trans. ASME
,
83
(
4
), pp.
441
444
.
21.
Hiromoto
,
U.
,
Yuji
,
S.
, and
Hiromichi
,
F.
,
1982
, “
Turbulence Measurements and Mass Transfer in Fully Developed Flow in a Triangular Duct With a Narrow Apex Angle
,”
Int. J. Heat Mass Transfer
,
25
(
5
), pp.
615
624
.
22.
Daschiel
,
G.
,
Frohnapfel
,
B.
, and
Jovanović
,
J.
,
2013
, “
Numerical Investigation of Flow Through a Triangular Duct: The Coexistence of Laminar and Turbulent Flow
,”
Int. J. Heat Fluid Flow
,
41
, pp.
27
33
.
23.
Baek
,
S.
,
Lee
,
S.
,
Hwang
,
W.
, and
Park
,
J. S.
,
2019
, “
Experimental and Numerical Investigation of the Flow in a Trailing Edge Ribbed Internal Cooling Passage
,”
ASME J. Turbomach.
,
141
(
1
), p.
011012
.
24.
Wright
,
L. M.
,
Liu
,
Y. H.
, and
Han
,
J. C.
,
2008
, “
Heat Transfer in Trailing Edge, Wedge-Shaped Cooling Channels Under High Rotation Numbers
,”
ASME J. Heat Transfer-Trans. ASME
,
130
(
7
), p.
071701
.
25.
Liu
,
Y. H.
,
Huh
,
M.
, and
Han
,
J. C.
,
2012
, “
High Rotation Number Effect on Heat Transfer in Trailing Edge Channel With Tapered Ribs
,”
Int. J. Heat Fluid Flow
,
33
(
1
), pp.
182
192
.
26.
Kim
,
S.
,
Suh
,
S.
,
Baek
,
S.
, and
Hwang
,
W.
,
2020
, “
Influence of Ribs on Internal Heat Transfer and Pressure Drop in a Turbine Blade Trailing Edge Channel
,”
Proceedings ASME Turbo Expo 2020
,
London, England
, Paper No. GT2020-14847.
27.
Gustavsson
,
J.
,
Hylén
,
J.
,
Kinell
,
M.
, and
Utriainen
,
E.
,
2010
, “
Window Temperature Impact on IR Thermography for Heat Transfer Measurements
,”
Proceedings of 48th AIAA Aerospace Sciences Meeting
,
Orlando, FL
, Paper No. AIAA-2010-0670.
28.
Kawamura
,
H.
,
Ohsaka
,
K.
,
Abe
,
H.
, and
Yamamoto
,
K.
,
1998
, “
DNS of Turbulent Heat Transfer in Channel Flow With Low to Medium-High Prandtl Number Fluid
,”
Int. J. Heat Fluid Flow
,
19
(
5
), pp.
482
491
.
29.
Lee
,
S.
, and
Hwang
,
W.
,
2019
, “
Development of an Efficient Immersed-Boundary Method With Subgrid-Scale Models for Conjugate Heat Transfer Analysis Using Large Eddy Simulation
,”
Int. J. Heat Mass Transfer
,
134
, pp.
198
208
.
30.
Moffat
,
R. J.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
,
1
(
1
), pp.
3
17
.
31.
Aliaga
,
D.
,
Lamb
,
J.
, and
Klein
,
D. E.
,
1994
, “
Convection Heat Transfer Distributions Over Plates With Square Ribs From Infrared Thermography Measurements
,”
Int. J. Heat Mass Transfer
,
37
(
3
), pp.
363
374
.
32.
Holmén
,
V.
,
2012
, “
Methods for Vortex Identification
,”
Master’s thesis
,
Lund University
,
Sweden
.
33.
Zhu
,
J.
,
Gao
,
T.
,
Li
,
J.
,
Li
,
G.
, and
Gong
,
J.
,
2014
, “
The Effect of Vortex Core Distribution on Heat Transfer in Steam Cooling of Gas Turbine Blade Internal Ribbed Channels
,”
Proceedings ASME Turbo Expo 2014
,
Düsseldorf, Germany
, Paper No. GT2014-25324.
34.
Capobianchi
,
M.
,
Irvine
,
T.
, and
Thomas
,
F.
,
1997
, “Triangular Ducts, Flow and Heat Transfer,”
International Encyclopedia of Heat & Mass Transfer
,
CRC Press
,
Boca Raton, FL
.
35.
Domaschke
,
N.
,
von Wolfersdorf
,
J.
, and
Semmler
,
K.
,
2012
, “
Heat Transfer and Pressure Drop Measurements in a Rib Roughened Leading Edge Cooling Channel
,”
ASME J. Turbomach.
,
134
(
6
), p.
061006
.
36.
Webb
,
R. L.
, and
Eckert
,
E. R. G.
,
1972
, “
Application of Rough Surfaces to Heat Exchanger Design
,”
Int. J. Heat Mass Transfer
,
15
(
9
), pp.
1649
1658
.
37.
Han
,
J. C.
,
Dutta
,
S.
, and
Ekkad
,
S.
,
2012
,
Gas Turbine Heat Transfer and Cooling Technology
,
Taylor and Francis
,
New York
.
You do not currently have access to this content.