Abstract

An experimental study was conducted to investigate the influence of mainstream oscillations on spatio-temporal variation of leading-edge film cooling effectiveness. The investigation utilized fast-response pressure-sensitive paint (Fast-PSP) technique at high frame rate. During the experiment, coolant (i.e., CO2, DR = 1.53) was discharged into three rows of cylindrical holes. Various blowing ratios (i.e., M = 0.50, 0.75, 1.00, and 1.50) were tested under the steady (i.e., f = 0 Hz) and oscillating (i.e., f = 7 Hz and 25 Hz) conditions. The measured instantaneous effectiveness was analyzed in terms of time-averaged and phase-averaged results. The results revealed that the mainstream oscillation, consisting of simultaneous pressure and velocity oscillation, significantly influences the behavior of the film cooling effectiveness. The time-averaged effectiveness significantly decreased at high oscillating frequency (i.e., 13.0–19.8% reduction at M = 0.50, f = 25 Hz compared with f = 0 Hz), especially at low blowing ratios (i.e., M = 0.50 and 0.75). The phase-averaged results captured significant decay in the film distributions associated with backflow caused by negative pressure gradients in coolant holes at certain phases. However, the mainstream oscillation effect was relatively insignificant at high blowing ratios (i.e., M = 1.00 and 1.50), which revealed the robustness of coolant coverage at low coolant Strouhal number (i.e., high blowing ratio) under the same oscillating frequency. Furthermore, the unsteady coolant intermittency showed highly unstable film coverage at high coolant Strouhal number. The coolant decay associated with backflow at high coolant Strouhal number should be considered by the gas-turbine designers in order to improve the lifecycle of turbine blades.

References

1.
Fawcett
,
R. J.
,
Wheeler
,
A. P. S.
,
He
,
L.
, and
Taylor
,
R.
,
2011
, “
Experimental Investigation Into Unsteady Effects on Film Cooling
,”
ASME J. Turbomach.
,
134
(
2
), p.
021015
. 10.1115/1.4003053
2.
Kohli
,
A.
, and
Bogard
,
D. G.
,
2011
, “
Fluctuating Thermal Field in the Near-Hole Region for Film Cooling Flows
,”
ASME J. Turbomach.
,
120
(
1
), pp.
86
91
. 10.1115/1.2841393
3.
Mick
,
W. J.
, and
Mayle
,
R. E.
,
1988
, “
Stagnation Film Cooling and Heat Transfer, Including Its Effect Within the Hole Pattern
,”
ASME J. Turbomach.
,
110
(
1
), pp.
66
72
. 10.1115/1.3262169
4.
Ou
,
S.
,
Mehendale
,
A. B.
, and
Han
,
J. C.
,
1992
, “
Influence of High Mainstream Turbulence on Leading Edge Film Cooling Heat Transfer: Effect of Film Hole Row Location
,”
ASME J. Turbomach.
,
114
(
4
), pp.
716
723
. 10.1115/1.2928024
5.
Ou
,
S.
, and
Rivir
,
R. B.
,
2001
, “
Leading Edge Film Cooling Heat Transfer With High Free Stream Turbulence Using a Transient Liquid Crystal Image Method
,”
Int. J. Heat Fluid Flow
,
22
(
6
), pp.
614
623
. 10.1016/S0142-727X(01)00121-7
6.
Reiss
,
H.
, and
Bölcs
,
A.
,
1999
, “
Experimental Study of Showerhead Cooling on a Cylinder Comparing Several Configurations Using Cylindrical and Shaped Holes
,”
Proc. ASME Turbo Expo
,
3
, pp.
1
10
. 10.1115/99-gt-123
7.
Azzi
,
A.
, and
Jubran
,
B. A.
,
2004
, “
Influence of Leading-Edge Lateral Injection Angles on the Film Cooling Effectiveness of a Gas Turbine Blade
,”
Heat Mass Transf. und Stoffuebertragung
,
40
(
6–7
), pp.
501
508
. 10.1007/s00231-003-0457-5
8.
Chowdhury
,
N. H. K.
,
Qureshi
,
S. A.
,
Zhang
,
M.
, and
Han
,
J. C.
,
2017
, “
Influence of Turbine Blade Leading Edge Shape on Film Cooling With Cylindrical Holes
,”
Int. J. Heat Mass Transfer
,
115
, pp.
895
908
. 10.1016/j.ijheatmasstransfer.2017.08.020
9.
Rozati
,
A.
, and
Tafti
,
D. K.
,
2008
, “
Effect of Coolant-Mainstream Blowing Ratio on Leading Edge Film Cooling Flow and Heat Transfer—LES Investigation
,”
Int. J. Heat Fluid Flow
,
29
(
4
), pp.
857
873
. 10.1016/j.ijheatfluidflow.2008.02.007
10.
Ligrani
,
P. M.
,
Gong
,
R.
,
Cuthrell
,
J. M.
, and
Lee
,
J. S.
,
1996
, “
Bulk Flow Pulsations and Film Cooling—I. Injectant Behavior
,”
Int. J. Heat Mass Transfer
,
39
(
11
), pp.
2271
2282
. 10.1016/0017-9310(95)00286-3
11.
Ligrani
,
P. M.
,
Gong
,
R.
,
Cuthrell
,
J. M.
, and
Lee
,
J. S.
,
1996
, “
Bulk Flow Pulsations and Film Cooling—II. Flow Structure and Film Effectiveness
,”
Int. J. Heat Mass Transfer
,
39
(
11
), pp.
2283
2292
. 10.1016/0017-9310(95)00287-1
12.
Baek
,
S. I.
, and
Yavuzkurt
,
S.
,
2018
, “
Effects of Oscillations in the Main Flow on Film Cooling at Various Frequencies at a Low Blowing Ratio
,”
Proc. ASME Turbo Expo, 5A-2018
,
Oslo, Norway
,
June 11–15
.
13.
Borup
,
D. D.
,
Fan
,
D.
,
Elkins
,
C. J.
, and
Eaton
,
J. K.
,
2019
, “
Experimental Study of Periodic Free Stream Unsteadiness Effects on Discrete Hole Film Cooling in Two Geometries
,”
ASME J. Turbomach.
,
141
(
6
), p.
061006
. 10.1115/1.4041866
14.
Zhou
,
W.
,
Qenawy
,
M.
,
Liu
,
Y.
,
Wen
,
X.
, and
Peng
,
D.
,
2019
, “
Influence of Mainstream Flow Oscillations on Spatio-Temporal Variation of Adiabatic Film Cooling Effectiveness
,”
Int. J. Heat Mass Transfer
,
129
, pp.
569
579
. 10.1016/j.ijheatmasstransfer.2018.09.131
15.
Zhou
,
W.
,
Chen
,
H.
,
Liu
,
Y.
,
Wen
,
X.
, and
Peng
,
D.
,
2018
, “
Unsteady Analysis of Adiabatic Film Cooling Effectiveness for Discrete Hole With Oscillating Mainstream Flow
,”
Phys. Fluids
,
30
(
12
), p.
127103
. 10.1063/1.5055028
16.
Ekkad
,
S. V.
,
Ou
,
S.
, and
Rivir
,
R. B.
,
2006
, “
Effect of Jet Pulsation and Duty Cycle on Film Cooling From a Single Jet on a Leading Edge Model
,”
ASME J. Turbomach.
,
128
(
3
), pp.
564
571
. 10.1115/1.2185122
17.
Johnson
,
R.
,
Maikell
,
J.
,
Bogard
,
D.
,
Piggush
,
J.
,
Kohli
,
A.
, and
Blair
,
M.
,
2009
, “
Experimental Study of the Effects of an Oscillating Approach Flow on Overall Cooling Performance of a Simulated Turbine Blade Leading Edge
,”
Proc. ASME Turbo Expo
,
3
(
Part B
), pp.
1009
1016
. 10.1115/gt2009-60290
18.
El-Gabry
,
L. A.
, and
Rivir
,
R. B.
,
2011
, “
Effect of Pulsed Film Cooling on Leading Edge Film Effectiveness
,”
ASME J. Turbomach.
,
134
(
4
), p.
041005
. 10.1115/1.4003653
19.
Shadid
,
J. N.
, and
Eckert
,
E. R. G.
,
2008
, “
The Mass Transfer Analogy to Heat Transfer in Fluids With Temperature-Dependent Properties
,”
ASME J. Turbomach.
,
113
(
1
), pp.
27
33
. 10.1115/1.2927734
20.
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
,”
Proc. ASME Turbo Expo
,
Orlando, FL
,
June 8–12
.
21.
Zhou
,
W.
,
Peng
,
D.
,
Liu
,
Y.
, and
Hu
,
H.
,
2019
, “
Assessment of Film Cooling’s Surface Quantities Using Pressure- and Temperature-Sensitive Paint: Comparisons Between Shaped and Sand-Dune Inspired Holes
,”
Exp. Therm. Fluid Sci.
,
101
, pp.
16
26
. 10.1016/j.expthermflusci.2018.10.005
22.
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
. 10.1016/j.ijheatmasstransfer.2018.04.126
23.
Scroggin
,
A. M.
,
Slamovich
,
E. B.
,
Crafton
,
J. W.
,
Lachendro
,
N.
, and
Sullivan
,
J. P.
,
1999
, “
Porous Polymer/Ceramic Composites for Luminescence-Based Temperature and Pressure Measurement
,”
MRS Proc.
,
560
, pp.
347
352
. 10.1557/PROC-560-347
24.
Peng
,
D.
,
Jensen
,
C. D.
,
Juliano
,
T. J.
,
Gregory
,
J. W.
,
Crafton
,
J.
,
Palluconi
,
S.
, and
Liu
,
T.
,
2013
, “
Temperature-Compensated Fast Pressure-Sensitive Paint
,”
AIAA J.
,
51
(
10
), pp.
2420
2431
. 10.2514/1.J052318
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
), pp.
1
17
. 10.1007/s00348-016-2130-z
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
. 10.1115/1.4033506
You do not currently have access to this content.