The fluid mechanics and heat transfer characteristics of film cooling are three-dimensional and highly complex. To understand this problem better, an experimental study was conducted in a low-speed wind tunnel on a row of six rectangular jets injected at 90 deg to the crossflow (mainstream flow). The jet-to-crossflow velocity ratios (blowing ratios) examined were 0.5, 1.0, and 1.5, and the jet spacing-to-jet width ratio was 3.0. No significant temperature difference between jet and crossflow air was introduced. Mean velocities and six flow stresses were measured using a three-component laser-Doppler velocimeter operating in coincidence mode. Seeding of both jet and cross-stream air was achieved with a commercially available smoke generator. Flow statistics are reported in the form of vector plots, contours, and x-y graphs, showing velocity, turbulence intensity, and Reynolds stresses. To complement the detailed measurements, flow visualization was accomplished by transmitting the laser beam through a cylindrical lens, thereby generating a narrow, intense sheet of light. Jet air only was seeded with smoke, which was illuminated in the plane of the light sheet. Therefore, it was possible to record on video tape the trajectory and penetration of the jets in the crossflow. Selected still images from the recordings are presented. Numerical simulations of the observed flow field were made by using a multigrid, segmented, k–ε CFD code. Special near-wall treatment included a nonisotropic formulation for the effective viscosity, a low-Re model for k, and an algebraic model for the length scale. Comparisons between the measured and computed velocities show good agreement for the nonuniform mean flow at the jet exit plane. Velocities and stresses on the jet centerline downstream of the orifice are less well predicted, probably because of inadequate turbulence modeling, while values off the centerline match those of the experiments much more closely.

Issue Section:
Research Papers
Topics:
Computer simulation, Jets, Flow (Dynamics), Stress, Smoke, Turbulence, Algebra, Computational fluid dynamics, Film cooling, Flow visualization, Fluid mechanics, Generators, Heat transfer, Laser beams, Lasers, Lenses (Optics), Modeling, Statistics, Temperature, Trajectories (Physics), Velocimeters, Viscosity, Wind tunnels
1.
Andreopoulos
J.
,
1985
, “
On the Structure of Jets in a Cross Flow
,”
Journal of Fluid Mechanics
, Vol.
138
, pp.
93
–
127
.
2.
Andreopoulos
J.
, and
Rodi
W.
,
1984
, “
Experimental Investigation of Jets in a Crossflow
,”
Journal of Fluid Mechanics
, Vol.
138
, pp.
93
–
127
.
3.
Beeck, A., Fottner, L., Benz, E., and Wittig, S., 1992, “The Aerodynamic Effect of Coolant Ejection in the Leading Edge Region of a Film-Cooled Turbine Blade,” Heat Transfer and Cooling in Gas Turbines, AGARD-CP-527, Paper No. 35.
4.
Benz, E., Wittig, S., Beeck, A., and Fottner, L., 1993, “Analysis of Cooling Jets Near the Leading Edge of Turbine Blades,” Computational and Experimental Assessment of Jets in Cross Flow, AGARD-CP-534, Paper No. 37.
5.
Demuren
A. O.
,
1993
, “
Characteristics of Three-Dimensional Turbulent Jets in Crossflow
,”
International Journal of Engineering Science
, Vol.
31
, No.
6
, pp.
899
–
913
.
6.
Edwards
R. V.
, ed.,
1987
, “
Report of the Special Panel on Statistical Particle Bias Problems in Laser Anemometry
,”
ASME Journal of Fluids Engineering
, Vol.
109
, pp.
89
–
93
.
7.
Foucault, E., Deniboire, P., and Bousgarbie`s, J.-L., 1992, “Etude Experimentale du Transfert de Chaleur Pre`s d’une Paroi Plane Chauffe´e en Pre´sence d’Injections Multiples (Ecoulement Subsonique),” Heat Transfer and Cooling in Gas Turbines, AGARD-CP-527, Paper No. 4.
8.
Fric, T. F., and Roshko, A., 1989, “Structure in the Near Field of the Transverse Jet,” Proc. 7th Symposium of Turbulent Shear Flows, pp. 6.4.1–6.4.6.
9.
Holdeman
J. D.
, and
Walker
R. E.
,
1977
, “
Mixing of a Row of Jets With a Confined Crossflow
,”
AIAA Journal
, Vol.
15
, pp.
243
–
249
.
10.
Isaac
K. M.
, and
Jakubowski
A. K.
,
1985
, “
Experimental Study of the Interaction of Multiple Jets in a Crossflow
,”
AIAA Journal
, Vol.
23
, No.
11
, pp.
1679
–
1683
.
11.
Kadotani
K.
, and
Goldstein
R. J.
,
1979
, “
On the Nature of Jets Entering a Turbulent Flow
,”
ASME Journal of Engineering for Power
, Vol.
101
, pp.
459
–
465
.
12.
Khan, Z. A., McGuirk, J. J., and Whitelaw, J. H., 1982, “A Row of Jets in Crossflow,” Fluid Dynamics of Jets With Application to V/STOL, AGARD-CP-308, Paper No. 10.
13.
Kim
S.-W.
, and
Benson
T. J.
,
1993
, “
Fluid Flow of a Row of Jets in Crossflow—A Numerical Study
,”
AIAA Journal
, Vol.
31
, No.
5
, pp.
806
–
811
.
14.
Kline, S. J., and McClintock, F. A., 1953, “Describing Uncertainties in Single-Sample Experiments,” Mechanical Engineering, Jan., pp. 3–8.
15.
McLaughlin
D. K.
, and
Tiederman
W. G.
,
1973
, “
Biasing Correction for Individual Realization of Laser Anemometer Measurements in Turbulent Flows
,”
Physics of Fluids
, Vol.
16
, pp.
2082
–
2088
.
16.
Nowak, P., 1991, “3-D Segmented Multi-Grid Computing Code,” Technical Report, Department of Mechanical Engineering, University of British Columbia, Vancouver, Canada.
17.
Pen˜a, F. Lo´pez, and Arts, T., 1992, “On the Development of a Film Cooling Layer,” Heat Transfer and Cooling in Gas Turbines, AGARD-CP-527, Paper No. 36.
18.
Perry, A. E., Kelso, R. M., and Lim, T. T., 1993, “Topological Structure of a Jet in a Cross Flow,” Computational and Experimental Assessment of Jets in Cross Flow, AGARD-CP-534, Paper No. 12.
19.
Sterland
P. R.
, and
Hollingsworth
M. A.
,
1975
, “
An Experimental Study of Multiple Jets Directed Normally to a Cross-Flow
,”
Journal of Mechanical Engineering Science
, Vol.
17
, No.
3
, pp.
117
–
124
.
20.
Sugiyama
Y.
, and
Usami
Y.
,
1979
, “
Experiments on the Flow in and Around Jets Directed Normal to a Crossflow
,”
Bulletin JSME
, Vol.
22
, pp.
1736
–
1795
.
21.
Zhou, J.-M., Salcudean, M., and Gartshore, I., 1993, “Prediction of Film Cooling by Discrete-Hole Injection,” ASME Paper No. 93-GT-75.
22.
Zhou, J.-M., 1994, “A Computational and Experimental Investigation of Gas Turbine Blade Film Cooling,” Ph.D. Thesis, University of British Columbia, Vancouver, Canada.
This content is only available via PDF.
Copyright © 1997
 by The American Society of Mechanical Engineers
You do not currently have access to this content.