Three-dimensional flowfields in a 60-deg curved combustor inlet duct of rectangular cross-section with and without guide vanes were measured using Laser-Doppler velocimetry for the longitudinal, radial, and spanwise velocity components. The Reynolds number based on the bulk mean velocity and hydraulic diameter was 2.53×104. The main parameters examined were the guide-vane number and Reynolds number. The results show that to completely eliminate flow separation in the curved combustor inlet three guide vanes should be installed. The critical Reynolds number for the absence of the flow separation is found to decrease with increasing product of radius and aspect ratios. In addition, it is found that in most regions the maximum radial mean velocity, difference between radial and spanwise normal stress, and the turbulent kinetic energy decrease with increasing guide-vane number. A rationale for the absence of flow separation in the one-vane case predicted by previous researchers is also provided.

Issue Section:
Technical Papers
Keywords:
flow separation, laser Doppler anemometry, turbulence
Topics:
Combustion chambers, Ducts, Flow (Dynamics), Flow separation, Guide vanes, Reynolds number, Turbulence, Uncertainty
1.
Ward-Smith, A. J., 1980, Internal Fluid Flow: The Fluid Dynamics of Flow in Pipes and Ducts, Oxford University Press, Oxford.
2.
Eustice
,
J.
,
1911
, “
Experiments on Stream-Line Motion in Curved Pipes
,”
Proc. R. Soc. London
,
85
, pp.
119
–
131
.
3.
Agrawal
,
Y.
,
Talbot
,
L.
, and
Gong
,
K.
,
1978
, “
Laser Anemometer Study of Flow Development in Curved Circular Pipes
,”
J. Fluid Mech.
,
85
, pp.
497
–
518
.
4.
Humphrey
,
J. A. C.
,
Taylor
,
A. M. K. P.
, and
Whitelaw
,
J. H.
,
1977
, “
Laminar Flow in a Square Duct of Strong Curvature
,”
J. Fluid Mech.
,
83
, pp.
509
–
527
.
5.
Humphrey
,
J. A. C.
,
Whitelaw
,
J. H.
, and
Yee
,
G.
,
1981
, “
Turbulent Flow in a Square Duct with Strong Curvature
,”
J. Fluid Mech.
,
103
, pp.
443
–
463
.
6.
Taylor
,
A. M. K. P.
,
Whitelaw
,
J. H.
, and
Yianneskis
,
M.
,
1982
, “
Curved Ducts with Strong Secondary Motion: Velocity Measurements of Developing Laminar and Turbulent Flow
,”
ASME J. Fluids Eng.
,
104
, pp.
350
–
359
.
7.
Chang
,
S. M.
,
Humphrey
,
J. A. C.
, and
Modavi
,
A.
,
1983
, “
Turbulent Flow in a Strongly Curved U-Bend and Downstream Tangent of Square Cross-Sections
,”
Physico-Chemical Hydrodynamics
,
4
, pp.
243
–
269
.
8.
Holt, M., Flores, J., and Turi, P. J., 1982, “Measurements of Air Flow in a Curved Pipe Using Laser-Doppler Velocimetry,” 1st International Symposium on Application of LDA to Fluid Mechanics, Lisbon, Portugal.
9.
Liou
,
T. M.
, and
Liu
,
C. H.
,
1986
, “
An Investigation of Pressure Loss and Mean Velocity Field in a Curved Square Duct with Different Reynolds Numbers
,”
Journal of the Chinese Society of Mechanical Engineers
,
7
, No.
4
, pp.
243
–
251
.
10.
Liou
,
T. M.
, and
Wu
,
S. M.
,
1987
, “
The Effect of Aspect Ratio on the Air Flow in Curved 90 Ducts with Uniform Inlet Condition
,”
Journal of the Chinese Institute of Engineers
,
10
, pp.
147
–
156
.
11.
Kotb
,
N. A. E.
,
Mokhtarzadeh-Dehghan
,
M. R.
, and
Ward-Smith
,
A. J.
,
1988
, “
A Numerical Study of Laminar and Turbulent Flows in a Two-Dimensional Bend with or without a Guide Vane
,”
Int. J. Numer. Methods Eng.
,
26
, pp.
245
–
262
.
12.
Liou
,
T. M.
, and
Liao
,
C. C.
,
1995
, “
Flows in a Curved Combustor Inlet with and Without a Guide Vane
,”
J. Propul. Power
,
11
, No.
3
, pp.
464
–
472
.
13.
Liou
,
T. M.
, and
Wu
,
S. M.
,
1988
, “
Flowfield in a Dual-Inlet Side-Dump Combustor
,”
J. Propul. Power
,
4
, No.
1
, pp.
53
–
60
.
14.
Tsai
,
M. K.
, and
Liou
,
T. M.
,
1991
, “
Study of Flow Induced by Nonuniform Lateral Injection
,”
J. Propul. Power
,
7
, No.
5
, pp.
668
–
677
.
15.
Liao, C. C., 1997, “A Study of Curved Duct Flows Associated with Side-Dump Combustor and Artery Disease,” Ph.D. thesis, Department of Power Mechanical Engineering, National Tsing Hua University, Hsin-Chu, Taiwain.
16.
Liou
,
T. M.
, and
Kao
,
C. F.
,
1988
, “
Symmetric and Asymmetric Turbulent Flows in a Rectangular Duct with a Pair of Ribs
,”
ASME J. Fluids Eng.
,
110
, pp.
373
–
379
.
17.
Drain, L. E., 1980, The Laser Doppler Technique, Wiley, New York, NY, pp. 136–145.
18.
Shahaf, M., Goldman, Y., and Greenberg, J. B., 1980, “An Investigation of Impinging Jets in Flow with Sudden Expansion,” Proceedings of the 22nd Israel Annual Conference on Aviation and Astronautics, pp. 100–106.
19.
Liou
,
T. M.
,
Hwang
,
Y. H.
, and
Wu
,
S. M.
,
1990
, “
The Three-Dimensional Jet-Jet Impingement Flow in a Closed-End Cylindrical Duct
,”
ASME J. Fluids Eng.
,
112
, pp.
171
–
178
.
20.
Rowe
,
M.
,
1970
, “
Measurements and computations of flow in pipe bends
,”
J. Fluid Mech.
,
43
, Part 4, pp.
771
–
783
.
21.
Melling
,
A.
, and
Whitelaw
,
J. H.
,
1976
, “
Turbulent Flow in a Rectangular Duct
,”
J. Fluid Mech.
,
78
, pp.
289
–
315
.
22.
Yokosawa
,
H.
,
Fujita
,
H.
,
Hirota
,
M.
, and
Iwata
,
S.
,
1989
, “
Measurement of Turbulent Flow in a Square Duct with Roughened Wall on Two Opposite Sides
,”
Int. J. Heat Fluid Flow
,
10
, pp.
125
–
130
.
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