Large eddy simulation of the 180 deg bend in a stationary ribbed duct is presented. The domain studied includes three ribs upstream of the bend region and three ribs downstream of the bend with an outflow extension added to the end, using a total of 8.4 million cells. Two cases are compared to each other: one includes a rib in the bend and the other does not. The friction factor, mean flow, turbulence, and heat transfer are compared in the two cases to help explain the benefits and disadvantages of the wide number of flow effects seen in the bend, including flow separation at the tip of the dividing wall, counter-rotating Dean vortices, high heat transfer at areas of flow impingement, and flow separation at the upstream and downstream corners of the bend. Mean flow results show a region of separated flow at the tip of the dividing region in the case with no rib in the bend, but no separation region is observed in the case with a rib. A pair of counter-rotating Dean vortices in the middle of the bend is observed in both cases. Turbulent kinetic energy profiles show a 30% increase in the midplane of the bend when the rib is added. High gradients of heat transfer augmentation are observed on the back wall and downstream outside wall, where mean flow impingement occurs. This heat transfer is increased with the presence of a rib. Including a rib in the bend increases the friction factor in the bend by 80%, and it increases the heat transfer augmentation by approximately 20%, resulting in a trade-off between pressure drop and heat transfer.

1.
Metzger
,
D. E.
, and
Sahm
,
M. K.
, 1986, “
Heat Transfer Around Sharp 180-deg Turns in Smooth Rectangular Channels
,”
ASME J. Heat Transfer
0022-1481,
108
, pp.
500
506
.
2.
Park
,
C. W.
, and
Lau
,
S. C.
, 1998, “
Effect of Channel Orientation of Local Heat (Mass) Transfer Distributions in a Rotating Two-Pass Square Channel With Smooth Walls
,”
ASME J. Heat Transfer
0022-1481,
120
, pp.
624
632
.
3.
Schabacker
,
J.
, and
Bölcs
,
A.
, 1998, “
PIV Investigation of the Flow Characteristics in an Internal Coolant Passage With Two Ducts Connected by a Sharp 180° Bend
,”
ASME Paper No. 98-GT-544
.
4.
Liou
,
T.-M.
,
Tzeng
,
Y.-Y.
, and
Chen
,
C.-C.
, 1999, “
Fluid Flow in a 180-deg Sharp Turning Duct With Different Divider Thicknesses
,”
ASME J. Turbomach.
0889-504X,
121
, pp.
569
576
.
5.
Mochizuki
,
S.
,
Takamura
,
J.
,
Yamawaki
,
S.
, and
Yang
,
W.-J.
, 1994, “
Heat Transfer in Serpentine Flow Passages With Rotation
,”
ASME J. Turbomach.
0889-504X,
116
, pp.
133
140
.
6.
Cardone
,
G.
,
Astarita
,
T.
, and
Carlomagno
,
G. M.
, 1998, “
Wall Heat Transfer in Static and Rotating 180d Turn Channels by Quantitative Infrared Thermography
,”
Rev. Gen. Therm.
0035-3159,
37
, pp.
644
652
.
7.
Besserman
,
D. L.
, and
Tanrikut
,
S.
, 1992, “
Comparison of Heat Transfer Measurements With Computations for Turbulent Flow Around a 180-deg Bend
,”
ASME J. Turbomach.
0889-504X,
114
, pp.
865
871
.
8.
Song
,
B.
, and
Amano
,
R. S.
, 2000, “
Application of Non-Linear k‐ω Model to the Turbulent Flow Inside a Sharp U-Bend
,”
ASME Paper No. 2000-GT-0225
.
9.
Gu
,
X.
,
Wu
,
H.-W.
,
Schock
,
H. J.
, and
Shih
,
T. I.-P.
, 2002, “
Two-Equation Versus Reynolds-Stress Modeling in Predicting Flow and Heat Transfer in a Smooth U-Duct With and Without Rotation
,”
ASME Paper No. GT-2002-30616
.
10.
Son
,
S. Y.
,
Kihm
,
K. D.
, and
Han
,
J.-C.
, 2002, “
PIV Flow Measurements for Heat Transfer Characterization in Two-Pass Square Channels With Smooth and 90° Ribbed Walls
,”
Int. J. Heat Mass Transfer
0017-9310,
45
, pp.
4809
4822
.
11.
Liou
,
T.-M.
,
Chen
,
M.-Y.
, and
Tsai
,
M.-H.
, 2002, “
Fluid Flow and Heat Transfer in a Rotating Two-Pass Square Duct With In-Line 90‐deg Ribs
,”
ASME J. Turbomach.
0889-504X,
124
, pp.
260
268
.
12.
Tse
,
D. G. N.
, and
Steuber
,
G. D.
, 1997, “
Flow in a Rotating Square Serpentine Coolant Passage With Skewed Trips
,”
ASME Paper No. 97-GT-529
.
13.
Iacovides
,
H.
,
Jackson
,
D. C.
,
Kelemenis
,
G.
,
Launder
,
B. E.
, and
Yuan
,
Y.-M.
, 2001, “
Flow and Heat Transfer in a Rotating U-Bend With 45° Ribs
,”
Int. J. Heat Fluid Flow
0142-727X,
22
, pp.
308
314
.
14.
Chanteloup
,
D.
,
Juaneda
,
Y.
, and
Bölcs
,
A.
, 2002, “
Combined 3D Flow and Heat Transfer Measurements in a 2-Pass Internal Coolant Passage of Gas Turbine Airfoils
,”
ASME Paper No. GT-2002-30214
.
15.
Servouse
,
Y.
, and
Sturgis
,
J. C.
, 2003, “
Heat Transfer and Flow Field Measurements in a Rib-Roughened Branch of a Rotating Two-Pass Duct
,”
ASME Paper No. GT2003-38048
.
16.
Ekkad
,
S. V.
, and
Han
,
J.-C.
, 1997, “
Detailed Heat Transfer Distributions in Two-Pass Square Channels With Rib Turbulators
,”
Int. J. Heat Mass Transfer
0017-9310,
40
, pp.
2525
2537
.
17.
Ekkad
,
S. V.
,
Pamula
,
G.
, and
Shantiniketanam
,
M.
, 2000, “
Detailed Heat Transfer Measurements Inside Straight and Tapered Two-Pass Channels With Rib Turbulators
,”
Exp. Therm. Fluid Sci.
0894-1777,
22
, pp.
155
163
.
18.
Chandra
,
P. R.
,
Han
,
J. C.
, and
Lau
,
S. C.
, 1988, “
Effect of Rib Angle on Local Heat∕Mass Transfer Distribution in a Two-Pass Rib-Roughened Channel
,”
ASME J. Turbomach.
0889-504X,
110
, pp.
233
241
.
19.
Mochizuki
,
S.
,
Murata
,
A.
,
Shibata
,
R.
, and
Yang
,
W.-J.
, 1999, “
Detailed Measurements of Local Heat Transfer Coefficients in Turbulent Flow Through Smooth and Rib-Roughened Serpentine Passages With a 180° Sharp Bend
,”
Int. J. Heat Mass Transfer
0017-9310,
42
, pp.
1925
1934
.
20.
Han
,
J. C.
,
Chandra
,
P. R.
, and
Lau
,
S. C.
, 1988, “
Local Heat∕Mass Transfer Distributions Around Sharp 180Deg Turns in Two-Pass Smooth and Rib-Roughened Channels
,”
ASME J. Heat Transfer
0022-1481,
110
, pp.
91
98
.
21.
Zhao
,
C. Y.
, and
Tao
,
W. Q.
, 1997, “
A Three Dimensional Investigation on Turbulent Flow and Heat Transfer Around Sharp 180‐Deg Turns in Two-Pass Rib-Roughened Channels
,”
Int. J. Heat Mass Transfer
0017-9310,
24
, pp.
587
596
.
22.
Bonhoff
,
B.
,
Tomm
,
U.
,
Johnson
,
B. V.
, and
Jennions
,
I.
, 1997, “
Heat Transfer Predictions for Rotating U-Shaped Coolant Channels With Skewed Ribs and With Smooth Walls
,”
ASME Paper No. 97-GT-162
.
23.
Stephens
,
M. A.
, and
Shih
,
T. I.-P.
, 1997, “
Computation of Compressible Flow and Heat Transfer in a Rotating Duct With Inclined Ribs and a 180‐Degree Bend
,”
ASME Paper No. 97-GT-192
.
24.
Shih
,
T. I.-P.
,
Lin
,
Y.-L.
,
Stephens
,
M. A.
, and
Chyu
,
M. K.
, 1998, “
Flow and Heat Transfer in a Ribbed U-Duct Under Typical Engine Conditions
,”
ASME Paper No. 98-GT-213
.
25.
Jang
,
Y.-J.
,
Chen
,
H.-C.
, and
Han
,
J.-C.
, 2000, “
Flow and Heat Transfer in a Rotating Square Channel With 45° Angled Ribs by Reynolds Stress Turbulence Model
,”
ASME Paper No. 2000-GT-0229
.
26.
Lin
,
Y.-L.
,
Shih
,
T. I.-P.
,
Stephens
,
M. A.
, and
Chyu
,
M. K.
, 2001, “
A Numerical Study of Flow and Heat Transfer in a Smooth and Ribbed U-Duct With and Without Rotation
,”
ASME J. Heat Transfer
0022-1481,
123
, pp.
219
232
.
27.
Al-Qahtani
,
M.
,
Jang
,
Y.-J.
,
Chen
,
H.-C.
, and
Han
,
J.-C.
, 2002, “
Prediction of Flow and Heat Transfer in Rotating Two-Pass Rectangular Channels With 45‐Deg Rib Turbulators
,”
ASME J. Turbomach.
0889-504X,
124
, pp.
242
250
.
28.
Ciofalo
,
M.
, and
Collins
,
M. W.
, 1992, “
Large-Eddy Simulation of Turbulent Flow and Heat Transfer in Plane and Rib-Roughened Channels
,”
Int. J. Opt. Comput.
1047-8507,
15
, pp.
453
489
.
29.
Braun
,
H.
,
Neumann
,
H.
, and
Mitra
,
N. K.
, 1999, “
Experimental and Numerical Investigation of Turbulent Heat Transfer in a Channel With Periodically Arranged Rib Roughness Elements
,”
Exp. Therm. Fluid Sci.
0894-1777,
19
, pp.
67
76
.
30.
Murata
,
A.
, and
Mochizuki
,
S.
, 2000, “
Large Eddy Simulation With a Dynamic Subgrid-Scale Model of Turbulent Heat Transfer in an Orthogonally Rotating Rectangular Duct With Transverse Rib Turbulators
,”
Int. J. Heat Mass Transfer
0017-9310,
43
, pp.
1243
1259
.
31.
Murata
,
A.
, and
Mochizuki
,
S.
, 2001, “
Comparison Between Laminar and Turbulent Heat Transfer in a Stationary Square Duct With Transverse or Angled Rib Turbulators
,”
Int. J. Heat Mass Transfer
0017-9310,
44
, pp.
1127
1141
.
32.
Murata
,
A.
, and
Mochizuki
,
S.
, 2001, “
Effect of Centrifugal Buoyancy on Turbulent Heat Transfer in an Orthogonally Rotating Square Duct With Transverse or Angled Rib Turbulators
,”
Int. J. Heat Mass Transfer
0017-9310,
44
, pp.
2739
2750
.
33.
Murata
,
A.
, and
Mochizuki
,
S.
, 2003, “
Effect of Cross-Sectional Aspect Ratio on Turbulent Heat Transfer in an Orthogonally Rotating Rectangular Duct With Angled Rib Turbulators
,”
Int. J. Heat Mass Transfer
0017-9310,
46
, pp.
3119
3133
.
34.
Jordan
,
S. A.
, 2003, “
The Turbulent Character and Pressure Loss Produced by Periodic Symmetric Ribs in a Circular Duct
,”
Int. J. Heat Fluid Flow
0142-727X,
24
, pp.
795
806
.
35.
Cui
,
J.
,
Patel
,
V.
, and
Lin
,
C.-L.
, 2003, “
Large-Eddy Simulation of Turbulent Flow in a Channel With Rib Roughness
,”
Int. J. Heat Fluid Flow
0142-727X,
24
, pp.
372
388
.
36.
Saha
,
A. K.
, and
Acharya
,
S.
, 2003, “
Flow and Heat Transfer in an Internally Ribbed Duct With Rotation: An Assessment of LES and URANS
,”
ASME Paper No. GT2003–38619
.
37.
Tyagi
,
M.
, and
Acharya
,
S.
, 2004, “
Large Eddy Simulations of Flow and Heat Transfer in Rotating Ribbed Duct Flows
,”
ASME Paper No. GT2004-53401
.
38.
Ahn
,
J.
,
Choi
,
H.
, and
Lee
,
J. S.
, 2004, “
Large Eddy Simulation of Flow and Heat Transfer in a Channel Roughened by Square or Semicircle Ribs
,”
ASME Paper No. GT2004-53924
.
39.
Watanabe
,
K.
, and
Takahashi
,
T.
, 2002, “
LES Simulation and Experimental Measurement of Fully Developed Ribbed Channel Flow and Heat Transfer
,”
ASME Paper No. GT-2002-30203
.
40.
Takahashi
,
T.
, and
Watanabe
,
K.
, 2004, “
Large Eddy Simulation of Flow and Heat Transfer in a Rectangular Channel With Crossed Angled Ribs
,”
ASME Paper No. GT2004-53673
.
41.
Tang
,
X.-L
,
Qian
,
Z.-D.
,
Wu
,
Y.-L.
,
Liu
,
S.-H.
, and
Yang
,
F.
, 2004, “
An Improved Dynamic Subgrid-Scale Stress Model
,”
J. Hydrodynam.
1001-6058,
16
, pp.
276
282
.
42.
Rütten
,
F.
,
Meinke
,
M.
, and
Schröder
,
W.
, 2001, “
Large-Eddy Simulations of 90° Pipe Bend Flows
,”
J. Turbul.
1468-5248,
2
, pp.
1
14
.
43.
Sewall
,
E. A.
, and
Tafti
,
D. K.
, 2004, “
Large Eddy Simulation of the Developing Region of a Stationary Ribbed Internal Turbine Blade Cooling Channel
,”
ASME Paper No. GT2004-53832
.
44.
Sewall
,
E. A.
, and
Tafti
,
D. K.
, 2004, “
Large Eddy Simulation of the Developing Region of a Rotating Ribbed Internal Turbine Blade Cooling Channel
,”
ASME Paper No. GT2004-53833
.
45.
Murata
,
A.
, and
Mochizuki
,
S.
, 2004, “
Large Eddy Simulation of Turbulent Heat Transfer in a Rotating Two-Pass Smooth Square Channel With Sharp 180° Turns
,”
Int. J. Heat Mass Transfer
0017-9310,
47
, pp.
683
698
.
46.
Murata
,
A.
, and
Mochizuki
,
S.
, 2004, “
Effect of Rib Orientation and Channel Rotation on Turbulent Heat Transfer in a Two-Pass Square Channel With Sharp 180° Turns Investigated by Using Large Eddy Simulation
,”
Int. J. Heat Mass Transfer
0017-9310,
47
, pp.
2599
2618
.
47.
Murata
,
A.
, and
Mochizuki
,
S.
, 2004, “
Centrifugal Buoyancy Effect on Turbulent Heat Transfer in a Rotating Two-Pass Smooth Square Channel With Sharp 180‐Deg Turns
,”
Int. J. Heat Mass Transfer
0017-9310,
47
, pp.
3215
3221
.
48.
Murata
,
A.
, and
Mochizuki
,
S.
, 2004, “
Aiding and Opposing Contributions of Centrifugal Buoyancy on Turbulent Heat Transfer in a Two-Pass Transverse- or Angled-Rib-Roughened Channel With Sharp 180° Turns
,”
Int. J. Heat Mass Transfer
0017-9310,
47
, pp.
3721
3743
.
49.
Germano
,
M.
,
Piomelli
,
U.
,
Moin
,
P.
, and
Cabot
,
W. H.
, 1991, “
A Dynamic Subgrid-Scale Eddy Viscosity Model
,”
Phys. Fluids A
0899-8213,
3
, pp.
1760
1765
.
50.
Tafti
,
D. K.
, 2005, “
Evaluating the Role of Subgrid Stress Modeling in a Ribbed Duct for the Internal Cooling of Turbine Blades
,”
Int. J. Heat Fluid Flow
0142-727X,
26
, pp.
92
104
.
51.
Tafti
,
D. K.
, 2001, “
GenIDLEST—A Scalable Parallel Computational Tool for Simulating Complex Turbulent Flows
,”
Proceedings of the ASME Fluids Engineering Division, FED
,
ASME-IMECE
, New York, p.
256
.
52.
Abdel-Wahab
,
S.
, and
Tafti
,
D. K.
, 2004, “
Large Eddy Simulation of Flow and Heat Transfer in a 90° Ribbed Duct With Rotation—Effect of Coriolis Forces
,”
ASME Paper No. GT2004-53796
.
53.
Abdel-Wahab
,
S.
, and
Tafti
,
D. K.
, 2004, “
Large Eddy Simulation of Flow and Heat Transfer in a 90° Ribbed Duct With Rotation—Effect of Buoyancy Forces
,”
ASME Paper No. GT2004-53799
.
54.
Abdel-Wahab
,
S.
, and
Tafti
,
D. K.
, 2004, “
Large Eddy Simulation of Flow and Heat Transfer in a Staggered 45° Ribbed Duct
,”
ASME Paper No. GT2004-53800
.
55.
Incropera
,
F. P.
, and
DeWitt
,
D. P.
, 2002,
Fundamentals of Heat and Mass Transfer
,
5th ed.
,
Wiley
, New York.
56.
Sewall
,
E. A.
,
Tafti
,
D. K.
,
Graham
,
A.
, and
Thole
,
K. A.
, 2005, “
Experimental Validation of Large Eddy Simulations of Flow and Heat Transfer in a Stationary Ribbed Duct
,”
Int. J. Heat Fluid Flow
0142-727X,
27
, pp.
243
258
.
57.
Han
,
J. C.
, 1988, “
Heat Transfer and Friction Characteristics in Rectangular Channels With Rib Turbulators
,”
ASME J. Heat Transfer
0022-1481,
110
, pp.
321
328
.
58.
Fann
,
S.
,
Yang
,
W.-J.
, and
Zhang
,
N.
, 1994, “
Local Heat Transfer in a Rotating Serpentine Passage With Rib-Roughened Surfaces
,”
Int. J. Heat Mass Transfer
0017-9310,
37
, pp.
217
228
.
59.
Taslim
,
M. E.
, and
Wadsworth
,
C. M.
, 1997, “
An Experimental Investigation of the Rib Surface-Averaged Heat Transfer Coefficient in a Rib-Roughened Square Passage
,”
ASME J. Turbomach.
0889-504X,
119
, pp.
381
389
.
You do not currently have access to this content.