Experiments were performed to investigate the local development of roughness and its effect on mass transfer in an S-shaped bend at Reynolds number of 200,000. The tests were performed over four consecutive time periods using a 203-mm-diameter test section with a dissolving gypsum lining to water in a closed flow loop at a Schmidt number of 1200. The surface roughness and the mass transfer over the test periods were measured using X-ray computed tomography (CT) scans of the surface. Two regions of high mass transfer are found: along the intrados of the first and second bends. The surface roughness in these two regions, characterized by the height-to-spacing ratio, grows more rapidly than in the upstream pipe. There is an increase in the mass transfer with time, which corresponds well with the local increase in the height-to-spacing ratio of the roughness. The two regions of high mass transfer enhancement in the bend can be attributed to both a roughness effect and a flow effect due to the bend geometry. The geometry effect was determined by normalizing the local mass transfer with that in a straight pipe with equivalent surface roughness. The mass transfer enhancement due to the geometry effect was found to be relatively constant for the two high mass transfer regions, with a value of approximately 1.5.

References

References
1.
Pietralik
,
J. M.
, and
Schefski
,
C. S.
,
2011
, “
Flow and Mass Transfer in Bends Under Flow-Accelerated Corrosion Wall Thinning Conditions
,”
ASME J. Eng. Gas Turbines Power
,
133
(
1
), p.
012902
.
2.
Poulson
,
B.
,
1999
, “
Complexities in Predicting Erosion Corrosion
,”
Wear
,
233–235
(
1999
), pp.
497
504
.
3.
El-Gammal
,
M.
,
Mazhar
,
H.
,
Cotton
,
J. S.
,
Schefski
,
C.
,
Pietralik
,
J.
, and
Ching
,
C. Y.
,
2010
, “
The Hydrodynamic Effects of Single Phase Flow on Flow Accelerated Corrosion in a 90° Elbow
,”
Nucl. Eng. Des.
,
240
(6), pp.
1589
1598
.
4.
Enayet
,
M. M.
,
Gibson
,
M. M.
,
Taylor
,
A. M. K. P.
, and
Yianneskis
,
M.
,
1982
, “
Laser-Doppler Measurements for Laminar and Turbulent Flow in Pipe Bend
,”
Int. J. Heat Fluid Flow
,
3
(
4
), pp.
213
220
.
5.
Sudo
,
K.
,
Sumida
,
M.
, and
Hibara
,
H.
,
1998
, “
Experimental Investigation on Turbulent Flow in a Circular-Sectioned 90-Degree Bend
,”
Experimental in Fluids
,
25
(1), pp.
42
49
.
6.
Achenbach
,
E.
,
1976
, “
Mass Transfer From Bends of Circular Cross Section to Air
,”
Future Energy Production System
, Vol.
1
,
Academic Press
,
New York
, pp.
327
337
.
7.
Sparrow
,
E. M.
, and
Chrysler
,
G. M.
,
1986
, “
Turbulent Flow and Heat Transfer in Bends of Circular Cross Section—Part I: Heat Transfer Experiments
,”
ASME J. Heat Transfer
,
108
(1), pp.
40
47
.
8.
Wilkin
,
S. J.
,
Oates
,
H. S.
, and
Coney
,
M.
,
1983
, “
Mass Transfer on Straight Pipes and 90° Bends Measured by the Dissolution of Plaster
,” 1st ed., Central Electricity Research Laboratories, Leatherhead, UK, Report No. TPRD/L/2469/N83.
9.
Mazhar
,
H.
,
Ewing
,
D.
,
Cotton
,
J. S.
, and
Ching
,
C. Y.
,
2013
, “
Experimental Investigation of Mass Transfer in 90° Pipe Bends Using a Dissolvable Wall Technique
,”
Int. J. Heat Mass Transfer.
,
65
, pp.
280
288
.
10.
Le
,
T.
,
Ewing
,
D.
,
Schefski
,
C.
, and
Ching
,
C. Y.
,
2014
, “
Mass Transfer in Back-to-Back Elbows Arranged in an out of Plane Configuration
,”
Nucl. Eng. Des.
,
270
, pp.
209
216
.
11.
Chen
,
X.
,
Le
,
T.
,
Ewing
,
D.
, and
Ching
,
C. Y.
,
2016
, “
Effect of Bend Separation Distance on the Mass Transfer in Back-to-Back Pipe Bends Arranged in a 180° Configuration
,”
Heat Mass Transfer
,
52
(12), pp.
2687
2695
.
12.
Mazhar
,
H.
,
Ewing
,
D.
,
Cotton
,
J. S.
, and
Ching
,
C. Y.
,
2014
, “
Mass Transfer in Dual Pipe Bends Arranged in an S-Configuration
,”
Int. J. Heat Mass Transfer
,
71
, pp.
747
757
.
13.
Wang
,
D.
,
Le
,
T.
,
Ewing
,
D.
, and
Ching
,
C. Y.
,
2016
, “
Measurement of Local Mass Transfer and the Resulting Roughness in a Large Diameter S-Bend at High Reynolds Number
,”
ASME J. Heat Transfer.
,
138
(
6
), p.
062001
.
14.
Dawson
,
A.
, and
Trass
,
O.
,
1972
, “
Mass Transfer at Rough Surfaces
,”
Int. J. Heat Mass Transfer
,
15
(7), pp.
1317
1336
.
15.
Tantiridge
,
S.
, and
Trass
,
O.
,
1984
, “
Mass Transfer at Geometrically Dissimilar Rough Surfaces. 1984
,”
Can. J. Chem. Eng.
,
62
(4), pp.
490
496
.
16.
Zhao
,
W.
, and
Trass
,
O.
,
1997
, “
Electrochemical Mass Transfer Measurements in Rough Surface Pipe Flow: Geometrically Similar V-Shaped Grooves
,”
Int. J. Heat Mass Transfer.
,
40
(
12
), pp.
2785
2797
.
17.
Lolja
,
S. A.
,
2005
, “
Momentum and Mass Transfer on Sandpaper-Roughened Surfaces in Pipe Flow
,”
Int. J. Heat Mass Transfer
,
48
(11), pp.
2209
2218
.
18.
Berger
,
F. P.
, and
Hau
,
K. F. F. L.
,
1979
, “
Local Mass/Heat Transfer Distribution on Surfaces Roughened With Small Square Ribs
,”
Int. J. Heat Mass Transfer
,
22
(12), pp.
1645
1656
.
19.
Villien
,
B.
,
Zheng
,
Y.
, and
Lister
,
D.
,
2005
, “
Surface Dissolution and the Development of Scallops
,”
Chem. Eng. Commun.
,
192
(
1
), pp.
125
136
.
20.
Thomas
,
R. M.
,
1979
, “
Size of Scallops and Ripples Formed by Flowing Water
,”
Nature
,
277
(
25
), pp.
281
283
.
21.
Wang
,
D.
,
Ewing
,
D.
, and
Ching
,
C. Y.
,
2016
, “
Time Evolution of Surface Roughness in Pipes Due to Mass Transfer Under Different Reynolds Numbers
,”
Int. J. Heat Mass Transfer
,
103
, pp.
661
671
.
22.
Wang
,
D.
,
Ewing
,
D.
, and
Ching
,
C. Y.
,
2017
, “
The Effect of Naturally Developing Roughness on the Mass Transfer in Pipes Under Different Reynolds Numbers
,”
ASME J. Heat Transfer
,
139
(
10
), p.
102005
.
23.
Ravigururajan
,
T. S.
, and
Bergles
,
A. E.
,
1996
, “
Development and Verification of General Correlations for Pressure Drop and Heat Transfer in Single-Phase Turbulent Flow in Enhanced Tubes
,”
Exp. Therm. Fluid Sci.
,
13
(1), pp.
55
70
.
24.
Postlethwaite
,
J.
, and
Lotz
,
U.
,
1988
, “
Mass Transfer at Erosion-Corrosion Roughened Surfaces
,”
Can. J. Chem. Eng.
,
66
(1), pp.
75
78
.
25.
Simpson
,
J. H.
, and
Carr
,
H. Y.
,
1958
, “
Diffusion and Nuclear Spin Relaxation in Water
,”
Phys. Rev.
,
111
(
5
), pp.
1201
1202
.
26.
Kline
,
S. J.
, and
McClintock
,
F. A.
,
1953
, “
Describing Uncertainties in Single Sample Experiments
,”
Mech. Eng.
,
75
(1), pp.
3
8
.
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