Abstract

The viewing angle for optical aerothermal measurements on turbine surfaces is often limited by the turbine structure, requiring the optical system to have a large depth of field (DoF). Although the DoF can be increased by decreasing the lens aperture, this approach is impractical as a large aperture is essential to maintain an acceptable signal-to-noise ratio (SNR). To solve these problems in the optical aerothermal measurements of film-cooled gas turbine blades, an approach combining the focal-sweep method and three-dimensional (3D) reconstruction is proposed. The focal-sweep method is used to obtain all-in-focus images at an inclined viewing angle, following which the two-dimensional image is restored through 3D reconstruction. Thus, 3D point clouds with both a large DoF and high SNR can be produced. The developed method was validated via flat-plate film cooling experiments using pressure-sensitive paint at three blowing ratios of 0.4, 0.8, and 1.2, as well as three viewing angles. The measured adiabatic effectiveness contours demonstrate that the proposed method can produce all-in-focus measurements at highly inclined viewing angles, albeit at the price of slightly higher noise. In flat-plate experiments, the maximum relative difference is measured to be 6% between results obtained by conventional method at normal view and the proposed method at highly inclined view. Furthermore, the proposed method was applied to the turbine blade cascade film cooling experiment at a highly inclined viewing angle, and successfully reconstructed the 3D point cloud of the cooling effectiveness at the curved turbine blade surface.

References

1.
Mhetras
,
S.
,
Han
,
J.-C.
, and
Rudolph
,
R.
,
2011
, “
Effect of Flow Parameter Variations on Full Coverage Film-Cooling Effectiveness for a Gas Turbine Blade
,”
ASME J. Turbomach.
,
134
(
1
), p.
011004
.
2.
Shiau
,
C.-C.
,
Chowdhury
,
N. H. K.
,
Han
,
J.-C.
,
Mirzamoghadam
,
A. V.
, and
Riahi
,
A.
,
2018
, “
Transonic Turbine-Vane Film Cooling With Showerhead Effect Using Pressure-Sensitive Paint Measurement Technique
,”
J. Thermophys. Heat Transfer
,
32
(
3
), pp.
637
647
.
3.
Zhou
,
W.
,
Qenawy
,
M.
,
Shao
,
H.
,
Peng
,
D.
,
Wen
,
X.
, and
Liu
,
Y.
,
2020
, “
Turbine Vane Endwall Film Cooling With Barchan-Dune Shaped Ramp in a Single-Passage Transonic Wind Tunnel
,”
Int. J. Heat Mass Transfer
,
162
, p.
120350
.
4.
Kunze
,
M.
,
Vogeler
,
K.
,
Brown
,
G.
,
Prakash
,
C.
, and
Landis
,
K.
,
2011
, “
Aerodynamic and Endwall Film-Cooling Investigations of a Gas Turbine Nozzle Guide Vane Applying Temperature-Sensitive Paint
,”
ASME J. Turbomach.
,
133
(
3
), p.
031027
.
5.
Wang
,
N.
,
Chen
,
A. F.
,
Zhang
,
M.
, and
Han
,
J.-C.
,
2018
, “
Turbine Blade Leading Edge Cooling With One Row of Normal or Tangential Impinging Jets
,”
ASME J. Heat Transfer-Trans. ASME
,
140
(
6
), p.
062201
.
6.
Lazzi Gazzini
,
S.
,
Schädler
,
R.
,
Kalfas
,
A. I.
, and
Abhari
,
R. S.
,
2016
, “
Infrared Thermography With Non-Uniform Heat Flux Boundary Conditions on the Rotor Endwall of an Axial Turbine
,”
Meas. Sci. Technol.
,
28
(
2
), p.
025901
.
7.
Peng
,
D.
,
Liu
,
Y.
,
Zhao
,
X.
, and
Kim
,
K. C.
,
2016
, “
Comparison of Lifetime-Based Methods for 2D Phosphor Thermometry in High-Temperature Environment
,”
Meas. Sci. Technol.
,
27
(
9
), p.
095201
.
8.
Nagahara
,
H.
,
Kuthirummal
,
S.
,
Zhou
,
C.
, and
Nayar
,
S. K.
,
Flexible Depth of Field Photography
,
Springer
,
Berlin Heidelberg
, pp.
60
73
.
9.
Ahn
,
J.
,
Schobeiri
,
M. T.
,
Han
,
J.-C.
, and
Moon
,
H.-K.
,
2007
, “
Effect of Rotation on Leading Edge Region Film Cooling of a gas Turbine Blade With Three Rows of Film Cooling Holes
,”
Int. J. Heat Mass Transfer
,
50
(
1
), pp.
15
25
.
10.
Peng
,
D.
,
Zhong
,
Z.
,
Gu
,
F.
,
Zhou
,
W.
,
Qi
,
F.
, and
Liu
,
Y.
,
2019
, “
Pressure-Sensitive Paint With Imprinted Pattern for Full-Field Endoscopic Measurement Using a Color Camera
,”
Sens. Actuators, A
,
290
, pp.
28
35
.
11.
Alaruri
,
S.
,
Bonsett
,
T.
,
Brewington
,
A.
,
McPheeters
,
E.
, and
Wilson
,
M.
,
1999
, “
Mapping the Surface Temperature of Ceramic and Superalloy Turbine Engine Components Using Laser-Induced Fluorescence of Thermographic Phosphor
,”
Opt. Lasers Eng.
,
31
(
5
), pp.
345
351
.
12.
Kodzwa
,
P. M.
, Jr
, and
Eaton
,
J. K.
,
2010
, “
Film Effectiveness Measurements on the Pressure Surface of a Transonic Airfoil
,”
J. Propul. Power
,
26
(
4
), pp.
837
847
.
13.
Dong
,
Z.
,
Liang
,
L.
,
Zhang
,
W.
,
Jiao
,
L.
,
Peng
,
D.
, and
Liu
,
Y.
,
2020
, “
Simultaneous Pressure and Deformation Field Measurement on Helicopter Rotor Blades Using a Grid-Pattern Pressure-Sensitive Paint System
,”
Measurement
,
152
, p.
107359
.
14.
Davidson
,
T. S.
,
Stokes
,
N. P.
,
Roberts
,
D. A.
, and
Quinn
,
M. K.
,
2019
, “
Time-Resolved Surface Pressure and Model Deformation Measurements in an Industrial Transonic Wind Tunnel
,”
AIAA Aviation 2019 Forum
,
Dallas, TX
,
June 17–21
and 19–21.
15.
Imai
,
M.
,
Nakakita
,
K.
,
Nakajima
,
T.
, and
Kameda
,
M.
,
2021
, “
Unsteady Surface Pressure Measurement of Transonic Flutter Using a Pressure Sensitive Paint With Random dot Pattern
,”
AIAA Scitech 2021 Forum
,
Virtual Event
,
Jan. 11–15
.
16.
Shi
,
S.
,
Xu
,
S.
,
Zhao
,
Z.
,
Niu
,
X.
, and
Quinn
,
M. K.
,
2018
, “
3D Surface Pressure Measurement With Single Light-Field Camera and Pressure-Sensitive Paint
,”
Exp. Fluids
,
59
(
5
), p.
79
.
17.
Li
,
Y.
,
Dong
,
Z.
,
Liang
,
L.
,
Liu
,
Y.
, and
Peng
,
D.
,
2021
, “
Simultaneous 3D Surface Profile and Pressure Measurement Using Phase-Shift Profilometry and Pressure-Sensitive Paint
,”
Rev. Sci. Instrum.
,
92
(
3
), p.
035107
.
18.
Suwajanakorn
,
S.
,
Hernandez
,
C.
, and
Seitz
,
S. M.
,
2015
, “
Depth From Focus With Your Mobile Phone
,”
Proceedings of 2015 IEEE Conference on Computer Vision and Pattern Recognition (CVPR)
,
Boston, MA
,
June 7–12
, pp.
3497
3506
.
19.
Krotkov
,
E.
,
1988
, “
Focusing
,”
Int. J. Comput. Vis.
,
1
(
3
), pp.
223
237
.
20.
Hartley
,
R.
, and
Zisserman
,
A.
,
2004
,
Multiple View Geometry in Computer Vision
,
Cambridge University Press
,
Cambridge
.
21.
Gortler
,
S.
,
2012
,
Foundations of 3D Computer Graphics
, Vol.
10
,
The MIT Press
,
Cambridge, MA
.
22.
Schroeder
,
R. P.
, and
Thole
,
K. A.
,
2014
, “
Adiabatic Effectiveness Measurements for a Baseline Shaped Film Cooling Hole
,”
Proceedings of ASME Turbo Expo 2014: Turbine Technical Conference and Exposition
,
Düsseldorf, Germany
,
June 16–20
, p. V05BT13A036.
23.
Baldauf
,
S.
,
Schulz
,
A.
, and
Wittig
,
S.
,
1999
, “
High-Resolution Measurements of Local Effectiveness From Discrete Hole Film Cooling
,”
ASME J. Turbomach.
,
123
(
4
), pp.
758
765
.
24.
Charbonnier
,
D.
,
Ott
,
P.
,
Jonsson
,
M.
,
Cottier
,
F.
, and
Köbke
,
T.
,
2009
, “
Experimental and Numerical Study of the Thermal Performance of a Film Cooled Turbine Platform
,”
Proceedings of ASME Turbo Expo 2009
,
Orlando, FL
,
June 8–12
, pp.
1027
1038
.
25.
Peng
,
D.
,
Wang
,
S.
, and
Liu
,
Y.
,
2016
, “
Fast PSP Measurements of Wall-Pressure Fluctuation in Low-Speed Flows: Improvements Using Proper Orthogonal Decomposition
,”
Exp. Fluids
,
57
(
4
), p.
45
.
26.
Johnson
,
B.
, and
Hu
,
H.
,
2016
, “
Measurement Uncertainty Analysis in Determining Adiabatic Film Cooling Effectiveness by Using Pressure Sensitive Paint Technique
,”
ASME J. Turbomach.
,
138
(
12
), p.
121004
.
27.
Wang
,
G.
,
Ledezma
,
G.
,
DeLancey
,
J.
, and
Wang
,
A.
,
2017
, “
Experimental Study of Effusion Cooling With Pressure-Sensitive Paint
,”
ASME J. Eng. Gas Turbines Power
,
139
(
5
), p.
051601
.
28.
Zhou
,
W.
,
Peng
,
D.
,
Wen
,
X.
,
Liu
,
Y.
, and
Hu
,
H.
,
2018
, “
Unsteady Analysis of Adiabatic Film Cooling Effectiveness Behind Circular, Shaped, and Sand-Dune–Inspired Film Cooling Holes: Measurement Using Fast-Response Pressure-Sensitive Paint
,”
Int. J. Heat Mass Transfer
,
125
, pp.
1003
1016
.
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