A new approach for steady-state heat transfer measurements is proposed. Temperature distributions are measured at the surface and a defined depth inside the wall to provide boundary conditions for a three-dimensional heat flux calculation. The practical application of the technique is demonstrated by employing a superposition method to measure heat transfer and film cooling effectiveness downstream of two different 0.75D deep narrow trench geometries and cylindrical holes. Compared to the cylindrical holes, both trench geometries lead to an augmentation of the heat transfer coefficient supposedly caused by the highly turbulent attached cooling film emanating from the trenches. Areas of high heat transfer are visible, where recirculation bubbles or large amounts of coolant are expected. Increasing the density ratio from 1.33 to 1.60 led to a slight reduction of the heat transfer coefficient and an increased cooling effectiveness. Both trenches provide a net heat flux reduction (NHFR) superior to that of cylindrical holes, especially at the highest momentum flux ratios.

References

References
1.
Behrendt
,
T.
,
Lengyel
,
T.
,
Hassa
,
C.
, and
Gerendas
,
M.
,
2008
, “
Characterization of Advanced Combustor Cooling Concepts Under Realistic Operating Conditions
,”
ASME
Paper No. GT2008-51191.
2.
Bunker
,
R. S.
,
2002
, “
Film Cooling Effectiveness Due to Discrete Holes Within a Transverse Surface Slot
,”
ASME
Paper No. GT2002-30178.
3.
Dorrington
,
J.
,
Bogard
,
D.
, and
Bunker
,
R.
,
2007
, “
Film Effectiveness Performance for Coolant Holes Embedded in Various Shallow Trench and Crater Depressions
,”
ASME
Paper No. GT2007-27992.
4.
Lu
,
Y.
,
Dhungel
,
A.
,
Ekkad
,
S.
, and
Bunker
,
R.
,
2009
, “
Effect of Trench Width and Depth on Film Cooling From Cylindrical Holes Embedded in Trenches
,”
ASME J. Turbomach.
,
131
(
1
), p.
011003
.
5.
Kröss
,
B.
, and
Pfitzner
,
M.
,
2012
, “
Numerical and Experimental Investigation of the Film Cooling Effectiveness and Temperature Field Behind a Novel Trench Configuration at High Blowing Ratio
,”
ASME
Paper No. GT2012-68125.
6.
Schreivogel
,
P.
,
Kröss
,
B.
, and
Pfitzner
,
M.
,
2014
, “
Density Ratio Effects on the Flow Field Emanating From Cylindrical Effusion and Trenched Film Cooling Holes
,”
ASME
Paper No. GT2014-25143.
7.
Schreivogel
,
P.
,
Kröss
,
B.
, and
Pfitzner
,
M.
,
2014
, “
Study of an Optimized Trench Film Cooling Configuration Using Scale Adaptive Simulation and Infrared Thermography
,”
ASME
Paper No. GT2014-25144.
8.
Eckert
,
E.
,
1984
, “
Analysis of Film Cooling and Full-Coverage Film Cooling of Gas Turbine Blades
,”
ASME J. Eng. Gas Turbines Power
,
106
(
1
), pp.
206
213
.
9.
Gritsch
,
M.
,
Baldauf
,
S.
,
Martiny
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
,
1999
, “
The Superposition Approach to Local Heat Transfer Coefficients in High Density Ratio Film Cooling Flows
,”
ASME
Paper No. 99-GT-168.
10.
Goldstein
,
R.
, and
Taylor
,
J.
,
1982
, “
Mass Transfer in the Neighborhood of Jets Entering a Crossflow
,”
ASME J. Heat Transfer
,
104
(
4
), pp.
715
721
.
11.
Goldstein
,
R.
,
Jin
,
P.
, and
Olson
,
L.
,
1999
, “
Film Cooling Effectiveness and Mass/Heat Transfer Coefficient Downstream of One Row of Discrete Holes
,”
ASME J. Turbomach.
,
121
(
2
), pp.
225
232
.
12.
Baldauf
,
S.
,
Schulz
,
A.
, and
Wittig
,
S.
,
2001
, “
High-Resolution Measurements of Local Heat Transfer Coefficients From Discrete Hole Film Cooling
,”
ASME J. Turbomach.
,
123
(
4
), pp.
749
757
.
13.
Ekkad
,
S.
,
Zapata
,
D.
, and
Han
,
J.
,
1997
, “
Heat Transfer Coefficients Over a Flat Surface With Air and CO2 Injection Through Compound Angle Holes Using a Transient Liquid Crystal Image Method
,”
ASME J. Turbomach.
,
119
(
3
), pp.
580
586
.
14.
Ammari
,
H.
,
Hay
,
N.
, and
Lampard
,
D.
,
1990
, “
The Effect of Density Ratio on the Heat Transfer Coefficient From a Film-Cooled Flat Plate
,”
ASME J. Turbomach.
,
112
(
3
), pp.
444
450
.
15.
Boyd
,
E.
,
McClintic
,
J.
,
Chavez
,
K.
, and
Bogard
,
D.
,
2014
, “
Direct Measurement of Heat Transfer Coefficient Augmentation at Multiple Density Ratios
,”
ASME
Paper No. GT2014-27085.
16.
Hakenesch
,
P.
,
1999
, “
Thin Layer Thermography—A New Heat Transfer Measurement Technique
,”
Exp. Fluids
,
26
(
3
), pp.
257
265
.
17.
Chambers
,
M.
, and
Clarke
,
D.
,
2009
, “
Doped Oxides for High-Temperature Luminescence and Lifetime Thermometry
,”
Annu. Rev. Mater. Res.
,
39
(
1
), pp.
325
359
.
18.
Schreivogel
,
P.
, and
Pfitzner
,
M.
,
2015
, “
Optical Convective Heat Transfer Measurements Using Infrared Thermography and Frequency Domain Phosphor Thermometry
,”
Int. J. Heat Mass Transfer
,
82
, pp.
299
308
.
19.
Ochs
,
M.
,
Horbach
,
T.
,
Schulz
,
A.
,
Koch
,
R.
, and
Bauer
,
H.-J.
,
2009
, “
A Novel Calibration Method for an Infrared Thermography System Applied to Heat Transfer Experiments
,”
Meas. Sci. Technol.
,
20
, pp.
1
9
.
20.
Seat
,
H.
,
Sharp
,
J.
,
Zhang
,
Z.
, and
Grattan
,
K.
,
2002
, “
Single-Crystal Ruby Fiber Temperature Sensor
,”
Sens. Actuators
, A,
101
(1--2), pp.
24
29
.
21.
Atakan
,
B.
,
Eckert
,
C.
, and
Pflitsch
,
C.
,
2009
, “
Light Emitting Diode Excitation of Cr3+:Al2O3 as Thermographic Phosphor: Experiments and Measurement Strategy
,”
Meas. Sci. Technol.
,
20
(
7
), p.
075304
.
22.
Aizawa
,
H.
,
Sekiguchi
,
M.
,
Katsumata
,
T.
,
Komuro
,
S.
, and
Morikawa
,
T.
,
2006
, “
Fabrication of Ruby Phosphor Sheet for the Fluorescence Thermometer Application
,”
Rev. Sci. Instrum.
,
77
, p.
044902
.
23.
Bouguet
,
J.-Y.
,
2013
, “
Camera Calibration Toolbox for Matlab
,” California Institute of Technology, Pasadena, CA, www.vision.caltech.edu/bouguetj/calib_doc/
24.
Baldauf
,
S.
,
Scheurlen
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
,
2002
, “
Heat Flux Reduction From Film Cooling and Correlation of Heat Transfer Coefficients From Thermographic Measurements at Enginelike Conditions
,”
ASME J. Turbomach.
,
124
(
4
), pp.
699
709
.
25.
Kays
,
W.
,
Crawford
,
M. E.
, and
Weigand
,
B.
,
2005
,
Convective Heat and Mass Transfer
,
McGraw-Hill
,
New York
.
26.
Moffat
,
R.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
,
1
(
1
), pp.
3
17
.
27.
Sinha
,
A.
,
Bogard
,
D.
, and
Crawford
,
M. E.
,
1991
, “
Film-Cooling Effectiveness Downstream of a Single Row of Holes With Variable Density Ratio
,”
ASME J. Turbomach.
,
113
(
3
), pp.
442
449
.
28.
Ammari
,
H.
,
Hay
,
N.
, and
Lampard
,
D.
,
1991
, “
Effect of Acceleration on the Heat Transfer Coefficient on a Film-Cooled Surface
,”
ASME J. Turbomach.
,
113
(
3
), pp.
464
471
.
29.
Saumweber
,
C.
, and
Schulz
,
A.
,
2012
, “
Free-Stream Effects on the Cooling Performance of Cylindrical and Fan-Shaped Cooling Holes
,”
ASME J. Turbomach.
,
134
(
6
), p.
061007
.
30.
Davidson
,
F.
,
Kistenmacher
,
D.
, and
Bogard
,
D.
,
2013
, “
Film Cooling With a Thermal Barrier Coating: Round Holes, Craters and Trenches
,”
ASME J. Turbomach.
,
136
(
4
), p.
041007
.
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