A study of flow in two stationary models of two-pass internal coolant passages is presented, which focuses on the flow characteristics in the 180-deg bend region, and downstream of the bend, where the flow is redeveloping. A stereoscopic digital PIV system measured all three velocity components simultaneously to obtain mean velocity, and turbulence quantities of the flow field. The coolant passage model consisted of two square passages, each having a 20 hydraulic diameter length, separated by a rounded-tip web of 0.2 passage widths, and connected by a sharp 180-deg bend with a rectangular outer wall. Ribs were mounted on the bottom and top walls of both legs, with a staggered arrangement, and at 45 deg to the flow. The rib height and spacing were 0.1 and 1.0 passage heights, respectively. The measurements were obtained for a flow condition, with a Reynolds number of 50,000. The geometries are similar in both sections except for one, which is equipped with extraction holes to simulate holes for film cooling. Two series of holes are placed solely in the bottom wall, four holes are located in the bend, and 12 in the downstream leg. The global extraction through the holes was set to 50% of the inlet massflow. This paper presents new measurements of the flow in the straight legs, as well as in the bend of the passage equipped with holes, detailed comparison of the flow upstream, inside and downstream of the bend region between both configurations, and the effects of extraction inside the cooling channels.

Issue Section:
Technical Papers
Keywords:
gas turbines, cooling, film flow, flow visualisation, laser velocimetry, heat transfer
Topics:
Flow (Dynamics), Coolants
1.
Rowbury, D., Parneix, S., Chanteloup, D., and Lees, A., 2001, Research into the influence of Rotation on the Internal Cooling Turbine Blades, Proc. AVT Symposium, Heat Transfer and Cooling in Propulsion and Power Systems, Loen, Norway.
2.
Rau
,
G.
,
Cakan
,
M.
,
Moeller
,
D.
, and
Arts
,
T.
,
1998
, “
The Effect of Periodic Ribs on the Local Aerodynamic and Heat Transfer Performance of a Straight Cooling Channel
,”
ASME J. Turbomach.
,
120
, pp.
368
–
375
.
3.
Schabacker, J., 1998, “PIV Investigation of the Flow Characteristics in an Internal Coolant Passages of Gas Turbine Airfoils With Two Ducts Connected by a Sharp 180 deg Bend,” Ph.D. thesis (Ecole Polytechnique fede´rale de Lausanne), Vol. no. 1816.
4.
Chanteloup, D., and Bo¨lcs, A. 2001, “PIV Investigation of the Flow Characteristics in 2-Leg Internal Coolant Passages of Gas Turbine Airfoils,” Proc. Euroturbo, 4th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics. Firenze, Italy.
5.
Bons
,
J. P.
, and
Kerrebrock
,
J. L.
,
1999
, “
Complementary velocity and heat transfer measurements in a rotating cooling passage with smooth walls
,”
ASME J. Turbomach.
,
121
, pp.
651
–
662
.
6.
Byerley, A. R., Jones, T. V., and Ireland, P. T., 1992, “Internal Cooling Passage Heat Transfer Near the Entrance to a Film Cooling Hole: Experimental and Computational Results,” 92-GT-241, Proc. Int Gas Turbine & Aeroengine Congress & Exhibition. Cologne, Germany.
7.
Shen
,
J. R.
,
Wang
,
Z.
,
Ireland
,
P. T.
, and
Jones
,
T. V.
,
1996
, “
Heat Transfer Enhancement Within a Turbine Blade Cooling Passage Using Ribs and Combinations of Ribs With Film Cooling Holes
,”
ASME J. Turbomach.
,
118
, July, pp.
428
–
434
.
8.
Lourenco, L. M., 1988, “Some Comments on Particle Image Displacement Velocimetry,” Lecture Series (Von Karman Institute for Fluid Dynamics), Vol. 06.
9.
Prasad
,
A. K.
, and
Adrian
,
R. J.
,
1993
, “Stereoscopic Particle Image Velocimetry Applied to Liquid Flows,”
Experiments in Fluids
,
15
, pp.
49
–
60
.
10.
Westerweel, J., and Nieuwstadt, F. T., 1991, “Performance Tests on 3-Dimensional Velocity Measurements with a Two-Camera Digital Particle-Image-Velocimeter,” Laser Anemometry, ASME, Vol. 1, pp. 349–355.
11.
Schabacker, J., and Bo¨lcs, A., 1996, “Investigation of Turbulent Flow by means of the PIV Method,” Proc. 13th Symposium on Measuring Techniques for Transonic and Supersonic Flows in Cascades and Turbomachines. Zurich, Switzerland.
12.
Johnson
,
B. V.
,
Wagner
,
J. H.
,
Steuber
,
G. D.
, and
Yeh
,
F. C.
,
1994
, “
Heat Transfer in Rotating Serpentine Passages With Trips Skewed to the Flow
,”
ASME J. Turbomach.
,
116
, pp.
113
–
123
.
13.
Han
,
J. C.
,
Zhang
,
P.
, and
Lee
,
C. P.
,
1992
, “
Influence of Surface Heat Flux Ratio on Heat Transfer Augmentation in Square Channels With Parallel, Crossed, and V-Shaped Angled Ribs
,”
ASME J. Turbomach.
,
114
, pp.
872
–
880
.
14.
Zhang
,
Y. M.
,
Han
,
J. C.
,
Parsons
,
J. A.
, and
Lee
,
C. P.
,
1995
, “
Surface Heating Effect on Local Heat Transfer in a Rotating Two-Pass Square Channel With 60 deg Rib Turbulators
,”
ASME J. Turbomach.
,
117
, pp.
272
–
278
.
15.
Schabacker, J., Bo¨lcs, A., and Johnson, B. V., 1998, “PIV Investigation of the Flow Characteristics in an Internal Coolant Passage With Two Ducts Connected by a Sharp 180 deg Bend,” 98-GT-544, Proc. International Gas Turbine & Aeroengine Congress & Exhibition. Stockholm, Sweden.
16.
Raffel, M., Willert, C. E., and Kompenhans, J., 1997, Particle Image Velocimetry. A Practical Guide (Springer), ISBN 3-540-63683-8.
17.
Bendat, J. S., and Piersol, A. G., 1986, “Random Data,” Random Data, (John Wiley & Sons, Inc.), New York, NY.
18.
Schabacker, J., and Bo¨lcs, A., 1998, “Investigation of Internal Flows by Means of the Stereoscopic PIV Method,” Proc., 9th Int. Symp. on Applications of Laser Techniques to Fluid Mechanics, Lisbon, Portugal.
19.
Bonhoff, B., Schabacker, J., Parneix, S., Leusch, J., Johnson, B. V., and Bo¨lcs, A., 1998, “Experimental and Numerical Study of Developed Flow and Heat Transfer in Coolant Channels with 45 and 90 deg Ribs,” 99-GT-123, Proc. Turbulent Heat Transfer II. Manchester, UK.
20.
Schabacker, J., Bo¨lcs, A., and Johnson, B. V., 1999, “PIV Investigation of the Flow Characteristics in an Internal Coolant Passage With 45 deg Rib Arrangement,” 99-GT-120, Proc. Int. Gas Turbine & Aeroengine Congress & Exhibition. Indianapolis, IN.
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