Heat transfer of air/water mist flow in a single-side heated vertical duct was experimentally investigated. The mist flow was produced by introducing fine dispersed water droplets into the air stream, and the water–air mass flow ratios were up to 15%. The Reynolds numbers of the air flow were 7900, 16,000, and 24,000. The rib spacing-to-height ratios were 10 and 20 in the current study. Mist flow cooling achieved higher heat transfer rates mainly because of the droplet deposition and liquid film formation on the heated surface. The heat transfer enhancement on the smooth surface by the mist flow was 4–6 times as high as the air flow. On the ribbed surface, a smaller rib spacing of 10 was preferred for air cooling, since the heat transfer enhancement by the flow reattachment was better utilized. However, the rib-induced secondary flow blew away the liquid films on the surface, and the heat transfer enhancement was degraded near the reattachment region for the mist cooling. A larger rib spacing-to-height ratio of 20 thus achieved higher heat transfer because of the liquid film formation beyond the reattachment region. The heat transfer enhancement on the ribbed surface using mist flow was 2.5–3.5 times as high as the air flow. The friction factor of the mist flow was two times as high as the air flow in the ribbed duct.

References

References
1.
Heyt
,
J. W.
, and
Larsen
,
P. S.
,
1970
, “
Heat Transfer to Binary Mist Flow
,”
Int. J. Heat Mass Transfer
,
14
(
9
), pp.
1395
1405
.
2.
Toda
,
S.
,
1972
, “
A Study of Mist-Cooling (1st Report: Investigation of Mist Cooling)
,”
Heat Transfer Jpn. Res.
,
1
(
3
), pp.
39
50
.
3.
Toda
,
S.
,
1974
, “
A Study of Mist Cooling: Theory of Mist Cooling and Its Fundamental Experiments
,”
Heat Transfer Jpn. Res.
,
3
(
1
), pp.
1
44
.
4.
Aihara
,
T.
,
Taga
,
M.
, and
Haraguchi
,
T.
,
1979
, “
Heat Transfer From a Uniform Heat Flux Wedge in Air-Water Mist Flows
,”
Int. J. Heat Mass Transfer
,
22
(
1
), pp.
51
60
.
5.
Trela
,
M.
,
1981
, “
An Approximation Calculation of Heat Transfer During Flow of an Air-Water Mist Flow Along a Heated Flat Plate
,”
Int. J. Heat Mass Transfer
,
24
(
4
), pp.
749
755
.
6.
Fu
,
W. S.
, and
Wu
,
R. M.
,
1988
, “
Heat Transfer From an Isothermal Wedge in an Air-Water Mist Flow
,”
Int. J. Heat Mass Transfer
,
31
(
6
), pp.
1157
1195
.
7.
Fu
,
W. S.
, and
Yang
,
G. C.
,
1989
, “
Influence of Droplets' Trajectories and Size Distribution on Heat Transfer From a Wedge in an Air-Water Mist Flow
,”
Numer. Heat Transfer, Part A
,
16
(
2
), pp.
155
174
.
8.
Aihara
,
T.
,
Fu
,
W. S.
, and
Suzuki
,
Y.
,
1990
, “
Numerical Analysis of Heat and Mass Transfer From Horizontal Cylinders in Downward Flow of Air-Water Mist
,”
ASME J. Heat Transfer
,
112
(
2
), pp.
472
478
.
9.
Aihara
,
T.
,
1990
, “
Augmentation of Convective Heat Transfer by Gas-Liquid Mist
,”
International Heat Transfer Conference
, Jerusalem, Israel, Aug. 19–24, Vol.
1
, pp.
445
461
.
10.
Nakayama
,
W.
,
Kuwahara
,
H.
, and
Hirasawa
,
S.
,
1988
, “
Heat Transfer From Tubes Banks to Air/Water Mist Flow
,”
Int. J. Heat Mass Transfer
,
31
(
2
), pp.
449
460
.
11.
Hayashi
,
Y.
,
Takimoto
,
A.
,
Matsuda
,
O.
, and
Kitagawa
,
T.
,
1990
, “
Study on Mist Cooling for Heat Exchanger
,”
JSME Int. J.
,
33
(
2
), pp.
333
339
.
12.
Hayashi
,
Y.
,
Takimoto
,
A.
, and
Matsuda
,
O.
,
1991
, “
Heat Transfer From Tubes in Mist Flows
,”
Exp. Heat Transfer
,
4
(
4
), pp.
291
308
.
13.
Lee
,
S. L.
,
Yang
,
Z. H.
, and
Hsyua
,
Y.
,
1994
, “
Cooling of a Heated Surface by Mist Flow
,”
ASME J. Heat Transfer
,
116
(
1
), pp.
167
172
.
14.
Lee
,
S. L.
, and
Srinivasan
,
J.
,
1982
, “
A Laser Doppler Velocimetry Technique for In-Situ Local Measurement of Dilute Two-Phase Suspension Flow
,”
Engineering Application of Laser Velocimetry Symposium
, Phoenix, AZ, Nov. 14–19, pp.
117
125
.
15.
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
.
16.
Liou
,
T. M.
, and
Hwang
,
J. J.
,
1993
, “
Effect of Ridge Shapes on Turbulent Heat Transfer and Friction in a Rectangular Channel
,”
Int. J. Heat Mass Transfer
,
36
(
4
), pp.
931
940
.
17.
Taslim
,
M. E.
, and
Spring
,
S. D.
,
1994
, “
Effects of Turbulator Profile and Spacing on Heat Transfer and Friction in a Channel
,”
AIAA J. Thermophys. Heat Transfer
,
8
(
3
), pp.
555
562
.
18.
Liu
,
Y. H.
, and
Lai
,
S. Y.
,
2012
, “
Heat Transfer Augmentation in Rotating Triangular Channels With Discrete and V-Shaped Ribs
,”
AIAA J. Thermophys. Heat Transfer
,
26
(
4
), pp.
603
611
.
19.
Dhanasekaran
,
T. S.
, and
Wang
,
T.
,
2013
, “
Computational Analysis of Mist/Air Cooling in a Two-Pass Rectangular Rotating Channel With 45-deg Angled Rib Turbulator
,”
Int. J. Heat Mass Transfer
,
61
, pp.
554
564
.
20.
Elwekeel
,
F. N. M.
,
Zheng
,
Q.
, and
Abdala
,
A. M. M.
,
2014
, “
Numerical Study of Turbulent Flow Through Rib-Roughened Channels With Mist Injection
,”
ASME
Paper No. GT2014-25408.
21.
Zeng
,
J.
,
Gao
,
T.
,
Li
,
J.
,
Zhu
,
J.
, and
Fei
,
J.
,
2016
, “
Numerical Investigation on Flow and Heat Transfer Characteristics of Steam and Mist/Steam in Internal Cooling Channels With Different Rib Angles
,”
ASME
Paper No. GT2016-56812.
22.
Pan
,
G.
,
Shakal
,
J.
,
Lai
,
W.
,
Calabria
,
R.
, and
Massoli
,
P.
,
2006
, “
Spray Features Investigated by GSV: A New Planar Laser Technique
,”
Tenth International Conference on Liquid Atomization and Spray Systems
(
ICLASS
), Kyoto, Japan, Aug. 27–Sept. 1, Paper No. 06-283.
23.
Moffat
,
R. J.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
,
1
(
1
), pp.
3
17
.
24.
Webb
,
R. L.
,
Eckert
,
E. R. G.
, and
Goldstein
,
R. J.
,
1971
, “
Heat Transfer and Friction in Tubes With Repeated-Rib Roughness
,”
Int. J. Heat Mass Transfer
,
14
(
4
), pp.
601
617
.
25.
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
,
40
(
11
), pp.
2525
2537
.
26.
Mayo
,
I.
,
Arts
,
T.
,
EI-Habib
,
A.
, and
Parres
,
B.
,
2015
, “
Two-Dimensional Heat Transfer Distribution of a Rotating Ribbed Channel at Different Reynolds Numbers
,”
ASME J. Turbomach.
,
137
(
3
), pp.
1
11
.
27.
Šefko
,
Š.
, and
Edin
,
B.
,
2015
, “
Analysis of Droplet Deposition in a Vertical Air-Water Dispersed Flow
,”
Procedia Eng.
,
100
, pp.
105
114
.
28.
Ishii
,
M.
, and
Mishima
,
K.
,
1989
, “
Droplet Entrainment Correlation in Annular Two-Phase Flow
,”
Int. J. Heat Mass Transfer
,
32
(
10
), pp.
1835
1846
.
29.
Novak
,
V.
,
Sadowski
,
D. L.
,
Schoonover
,
K. G.
,
Abdel-Khalik
,
S. I.
, and
Ghiaasiaan
,
S. M.
,
2008
, “
Heat Transfer in Two-Component Internal Mist Cooling—Part I: Experimental Investigation
,”
Nucl. Eng. Des.
,
238
(
9
), pp.
2341
2350
.
30.
Chandra
,
P. R.
, and
Cook
,
M. M.
,
1994
, “
Effect of the Number of Channel Ribbed Walls on Heat Transfer and Friction Characteristics of Turbulent Flows
,”
Sixth AIAA/ASME Thermophysics and Heat Transfer Conference
, Colorado Springs, CO, June 20–23, pp.
201
209
.
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