An experimental and numerical study has been conducted on heat transfer and turbulent flow structure in channels with novel hybrid structures with miniature V-shaped ribs and dimples on one wall. One miniature V-shaped rib was arranged immediately upstream each individual dimple to form the hybrid structure, which aims at inducing additional near-wall secondary flow interacting with the dimple vortex flow and further improving the heat transfer. Steady-state convective heat transfer experiments were done to obtain the heat transfer and pressure loss of the turbulent flow over the surfaces with the miniature V rib-dimples for the Reynolds numbers from 18,700 to 60,000. In addition, the turbulent flow structure in the V rib-dimpled channels has been predicted by carrying out numerical computations. The experimental results indicated that the overall heat transfer enhancement of the miniature V rib-dimpled channels can be increased by up to about 60.0% compared with the counterpart of the dimpled only channel, and by about 23.0% compared with the counterpart of the miniature V ribbed only channel. The miniature V ribs showed appreciable effects on the heat transfer and pressure loss characteristics for the turbulent flow over the V rib-dimpled surfaces. The numerical computations showed that the miniature V rib upstream each dimple produced strong near-wall downwashing secondary flow, which significantly changed the flow patterns and intensified the turbulent flow mixing inside and outside the dimple and above the surrounding wall. These unique near-wall flow characteristics generated a significant heat transfer improvement in both the magnitude and the uniformity.

References

1.
Ligrani
,
P.
,
2013
, “
Heat Transfer Augmentation Technologies for Internal Cooling of Turbine Components of Gas Turbine Engines
,”
Int. J. Rotating Mach.
,
2013
, p.
1
.
2.
Han
,
J. C.
, and
Park
,
J. S.
,
1988
, “
Developing Heat Transfer in Rectangular Channels With Rib Turbulators
,”
Int. J. Heat Mass Transfer
,
31
(
1
), pp.
183
195
.
3.
Han
,
J. C.
, and
Zhang
,
Y. M.
,
1992
, “
High Performance Heat Transfer Ducts With Parallel Broken and V-Shaped Broken Ribs
,”
Int. J. Heat Mass Transfer
,
35
(
2
), pp.
513
523
.
4.
Afanasyev
,
V. N.
,
Chudnovsky
,
Y. P.
,
Leontiev
,
A. I.
, and
Roganov
,
P. S.
,
1993
, “
Turbulent Flow Friction and Heat Transfer Characteristics for Spherical Cavities on a Flat Plate
,”
Exp. Therm. Fluid Sci.
,
7
(
1
), pp.
1
8
.
5.
Ligrani
,
P. M.
,
Harrison
,
J. L.
,
Mahmmod
,
G. I.
, and
Hill
,
M. L.
,
2001
, “
Flow Structure Due to Dimple Depressions on a Channel Surface
,”
Phys. Fluids
,
13
(
11
), pp.
3442
3451
.
6.
Burgess
,
N. K.
, and
Ligrani
,
P. M.
,
2005
, “
Effects of Dimple Depth on Channel Nusselt Numbers and Friction Factors
,”
ASME J. Heat Transfer
,
127
(
8
), pp.
839
847
.
7.
Rao
,
Y.
,
Feng
,
Y.
,
Li
,
B.
, and
Weigand
,
B.
,
2015
, “
Experimental and Numerical Study of Heat Transfer and Flow Friction in Channels With Dimples of Different Shapes
,”
ASME J. Heat Transfer
,
134
(
12
), pp.
723
732
.
8.
Han
,
J. C.
, and
Chen
,
H. C.
,
2006
, “
Turbine Blade Internal Cooling Passages With Rib Turbulators
,”
AIAA J. Propul. Power
,
22
(
2
), pp.
226
248
.
9.
Tanda
,
G.
,
2004
, “
Heat Transfer in Rectangular Channels With Transverse and V-Shaped Broken Ribs
,”
Int. J. Heat Mass Transfer
,
47
(
2
), pp.
229
243
.
10.
Chang
,
S. W.
,
Liou
,
T. M.
, and
Lee
,
T. H.
,
2012
, “
Thermal Performance Comparison Between Radially Rotating Ribbed Parallelogram Channels With and Without Dimples
,”
Int. J. Heat Mass Transfer
,
55
(
13–14
), pp.
3541
3559
.
11.
Choi
,
E. Y.
,
Yong
,
D. C.
,
Lee
,
W. S.
,
Jin
,
T. C.
, and
Kwak
,
J. S.
,
2013
, “
Heat Transfer Augmentation Using a Rib–Dimple Compound Cooling Technique
,”
Appl. Therm. Eng.
,
51
(
1–2
), pp.
435
441
.
12.
Kunstmann
,
S.
,
Wolfersdorf
,
J.
, and
Ruedel
,
U.
,
2010
, “
Heat Transfer and Pressure Drop in Combustor Cooling Channels With Combinations of Geometrical Elements
,”
ASME
Paper No. GT2010-23234.
13.
Singh
,
P.
,
Jaideep
,
P.
, and
Ekkad
,
S. V.
,
2017
, “
Characterization of Heat Transfer Enhancement and Frictional Losses in a Two-Pass Square Duct Featuring Unique Combinations of Rib Turbulators and Cylindrical Dimples
,”
Int. J. Heat Mass Transfer
,
106
, pp.
629
647
.
14.
Marocco
,
L.
, and
Franco
,
A.
,
2016
, “
Direct Numerical Simulation and RANS Comparison of Turbulent Convective Heat Transfer in a Staggered Ribbed Channel With High Blockage
,”
ASME J. Heat Transfer
,
139
(
2
), p.
021701
.
15.
Hagari
,
T.
,
Ishida
,
K.
,
Oda
,
T.
,
Douura
,
Y.
, and
Kinoshita
,
Y.
,
2011
, “
Heat Transfer and Pressure Losses of W-Shaped Small Ribs at High Reynolds Numbers for Combustor Liner
,”
ASME J. Eng. Gas Turbines Power
,
133
(
9
), p.
091901
.
16.
Chang
,
S. W.
,
Liou
,
T. M.
,
Chiang
,
K. F.
, and
Hong
,
G. F.
,
2008
, “
Heat Transfer and Pressure Drop in Rectangular Channel With Compound Roughness of V-Shaped Ribs and Deepened Scales
,”
Int. J. Heat Mass Transfer
,
51
(
3–4
), pp.
457
468
.
17.
Rao
,
Y.
,
2014
, “
Cooling Device With Small Structured Rib-Dimple Hybrid Structures
,” Chinese Patent No. CN201410138196.0.
18.
Moffat
,
R. J.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
,
1
(
1
), pp.
3
17
.
19.
ANSYS
,
2014
, “ANSYS FLUENT CFD 15.0, The User's Guide,”
ANSYS
, Canonsburg, PA.
20.
Abe
,
K.
,
Kondoh
,
T.
, and
Nagano
,
Y.
,
1994
, “
A New Turbulence Model for Predicting Fluid Flow and Heat Transfer in Separating and Reattaching Flows-I. Flow Field Calculations
,”
Int. J. Heat Mass Transfer
,
37
(
1
), pp.
139
151
.
21.
Abe
,
K.
,
Kondoh
,
T.
, and
Nagano
,
Y.
,
1995
, “
A New Turbulence Model for Predicting Fluid Flow and Heat Transfer in Separating and Reattaching Flows-II. Thermal Field Calculations
,”
Int. J. Heat Mass Transfer
,
38
(
8
), pp.
1467
1481
.
22.
Rao
,
Y.
, and
Zhang
,
P.
,
2017
, “
Experimental Study of Heat Transfer and Pressure Loss in Channels With Miniature V Rib-Dimple Hybrid Structure
,”
13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics
(
HEFAT2017
), Portoroz, Slovenia, July 17--19, p. 1570345913.https://repository.up.ac.za/handle/2263/62405
23.
Zhang
,
P.
, and
Rao
,
Y.
,
2018
, “
A Numerical Study of Heat Transfer and Flow Structure in Channels With Miniature V Rib-Dimple Hybrid Structure on One Wall
,”
ASME
Paper No. GT2018-75929.
24.
Jak
,
E.
, and
Hayes
,
P. C.
,
2008
, “
Procedure of Estimation and Reporting of Uncertainty Due to Discretization in CFD Applications
,”
ASME J. Fluids Eng.
,
130
(
7
), p.
078001
.
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