Condenser performance benefits afforded by dropwise condensation have long been unattainable in steam cycle power plant condensers due to the unavailability of durable and long-lasting hydrophobic surface treatments. However, recent work in superhydrophobic coating technology shows promise that durable coatings, appropriate for use on condenser tubes in steam cycle power generation systems, may soon become a reality. This work presents a nanoscale, vapor phase deposited superhydrophobic coating with improved durability comprised of several layers of rough alumina nanoparticles and catalyzed silica with a finishing layer of perfluorinated silane. This coating was applied to solid, hemicylindrical test surfaces fabricated from several common condenser tube materials used in power generation system condensers: Titanium, Admiralty brass, Cupronickel, and Sea Cure stainless steel as well as 304 stainless steel stock. The development evolution of the coating and its effect on condensation behavior on the above materials are presented. Results show that the performance enhancement, measured in rate of heat transfer spikes corresponding to condensate roll-off events, was best for the titanium surface, which produced 64% more events than the next most active material when coated using the most durable surface treatment tested in this work.

References

References
1.
Verho
,
T.
,
Bower
,
C.
,
Andrew
,
P.
,
Franssila
,
S.
,
Ikkala
,
O.
, and
Ras
,
R. H. A.
,
2010
, “
Mechanically Durable Superhydrophobic Surfaces
,”
Adv. Mater.
,
23
(
5
), pp.
673
678
.
2.
Carey
,
V. P.
,
2008
,
Liquid-Vapor Phase Change Phenomena
,
2nd ed.
,
Taylor & Francis Group
,
New York
, pp.
418
419
.
3.
Boreyko
,
J. B.
, and
Chen
,
C. H.
,
2009
, “
Self-Propelled Dropwise Condensate on Superhydrophobic Surfaces
,”
Phys. Rev. Lett.
,
103
(
18
), p.
184501
.
4.
Manvel
,
J. T.
, Jr.
,
1979
, “
An Experimental Study of Dropwise Condensation on Horizontal Condenser Tubes
,”
Master's thesis
, Naval Postgraduate School, Monterey, CA.https://calhoun.nps.edu/handle/10945/18721
5.
Das
,
A. K.
,
Kilty
,
H. P.
,
Marto
,
P. J.
,
Andeen
,
G. B.
, and
Kumar
,
A.
,
2000
, “
The Use of and Organic Self-Assembled Monolayer Coating to Promote Dropwise Condensation of Steam on Horizontal Tubes
,”
ASME J. Heat Transfer
,
122
(
2
), pp.
278
286
.
6.
Chen
,
C. H.
,
Cai
,
Q. J.
,
Tsai
,
C. L.
,
Chen
,
C. L.
, and
Xiong
,
G. Y.
,
2007
, “
Dropwise Condensation on Superhydrophobic Surfaces With Two-Tier Roughness
,”
Appl. Phys. Lett.
,
90
(
17
), p.
173108
.
7.
Liang
,
Z.
, and
Keblinski
,
P.
,
2015
, “
Coalescence-Induced Jumping of Nanoscale Droplets on Super-Hydrophobic Surfaces
,”
Appl. Phys. Lett.
,
107
(
14
), p.
143105
.
8.
Zhang
,
K.
,
Liu
,
F.
,
Williams
,
A. J.
,
Qu
,
X.
,
Feng
,
J. J.
, and
Chen
,
C. H.
,
2015
, “
Self-Propelled Droplet Removal From Hydrophobic Fiber-Based Coalescers
,”
Phys. Rev. Lett.
,
115
(
7
), p.
074502
.
9.
Qu
,
X.
,
Boreyko
,
J. B.
,
Liu
,
F.
,
Agapov
,
R. L.
,
Larvik
,
N. V.
,
Retterer
,
S. T.
,
Feng
,
J. J.
,
Collier
,
C. P.
, and
Chen
,
C. H.
,
2015
, “
Self-Propelled Sweeping Removal of Dropwise Condensate
,”
Appl. Phys. Lett.
,
106
(
22
), p.
221601
.
10.
Miljkovic
,
N.
,
Enright
,
R.
,
Nam
,
Y.
,
Lopez
,
K.
,
Dou
,
N.
,
Sack
,
J.
, and
Wang
,
E. N.
,
2012
, “
Jumping-Droplet-Enhanced Condensation on Scalable Superhydrophobic Nanostructured Surfaces
,”
Nano Lett.
,
13
(
1
), pp.
179
187
.
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