Note
College of Engineering and Computer Science
Member of
Contributors
Publisher
Florida Atlantic University
Date Issued
1997
Description
Twenty-four test cells arranged in a pipe flow setup were assembled to
investigate the effect of seawater velocity on the polarization behavior of
galvanically polarized mild steel. Each 1023 steel pipe specimen of 10.8 em ID
was coupled via a current limiting resistor to a mercury activated aluminum
anode and exposed to a velocity of either 0.03, 0.09 or 0.30 m/s. The resistors
were sized such that polarization was controlled according to one of six slope
parameters. Steady state potential and maintenance current density values were
determined, and a steady state potential vs. current density curve was
established for specimens in each velocity. Some specimens experienced a rise in
cathode potential and current density after an apparent steady state had been
reached. This was probably related to the influence of velocity on the
protectiveness of the calcareous deposit. Of the specimens that experienced a
rise in steady state potential and current density, a few were later observed to
decrease in potential and current density and reach steady state. Steady state
current density vs. velocity plots of specimens at steady state potentials of -0.78,
-0.88 and -0.98 V showed that current density was directly proportional to
velocity as well as relatively insensitive to potential. Ficks' first law was utilized in conjunction with an empirically derived dimensionless correlation that
characterizes the behavior between fluid velocity and mass transfer of molecular
species from the bulk solution to the cathode surface in turbulent seawater pipe
flow. Calcareous deposit porosity constants were calculated and it was surmised
that as velocity increased by a factor of three, the porosity of the deposits near 0.78
and -0.89 V increased by multiples of about two on average. Porosity at the
above potentials increased with decreasing potential by a factor of a little over
two. SEM micrographs were made and EDX analyses were performed on the
calcareous deposits of selected specimens.
investigate the effect of seawater velocity on the polarization behavior of
galvanically polarized mild steel. Each 1023 steel pipe specimen of 10.8 em ID
was coupled via a current limiting resistor to a mercury activated aluminum
anode and exposed to a velocity of either 0.03, 0.09 or 0.30 m/s. The resistors
were sized such that polarization was controlled according to one of six slope
parameters. Steady state potential and maintenance current density values were
determined, and a steady state potential vs. current density curve was
established for specimens in each velocity. Some specimens experienced a rise in
cathode potential and current density after an apparent steady state had been
reached. This was probably related to the influence of velocity on the
protectiveness of the calcareous deposit. Of the specimens that experienced a
rise in steady state potential and current density, a few were later observed to
decrease in potential and current density and reach steady state. Steady state
current density vs. velocity plots of specimens at steady state potentials of -0.78,
-0.88 and -0.98 V showed that current density was directly proportional to
velocity as well as relatively insensitive to potential. Ficks' first law was utilized in conjunction with an empirically derived dimensionless correlation that
characterizes the behavior between fluid velocity and mass transfer of molecular
species from the bulk solution to the cathode surface in turbulent seawater pipe
flow. Calcareous deposit porosity constants were calculated and it was surmised
that as velocity increased by a factor of three, the porosity of the deposits near 0.78
and -0.89 V increased by multiples of about two on average. Porosity at the
above potentials increased with decreasing potential by a factor of a little over
two. SEM micrographs were made and EDX analyses were performed on the
calcareous deposits of selected specimens.
Language
Type
Form
Extent
94 p.
Subject (Topical)
Identifier
9780591625028
ISBN
9780591625028
Additional Information
College of Engineering and Computer Science
FAU Electronic Theses and Dissertations Collection
Thesis (M.S.)--Florida Atlantic University, 1997.
Date Backup
1997
Date Text
1997
Date Issued (EDTF)
1997
Extension
FAU
FAU
admin_unit="FAU01", ingest_id="ing1508", creator="staff:fcllz", creation_date="2007-07-19 04:27:21", modified_by="staff:fcllz", modification_date="2011-01-06 13:09:22"
IID
FADT15501
Issuance
monographic
Organizations
Attributed name: Florida Atlantic University
Person Preferred Name
Hugus, G. Dickson, IV.
Graduate College
Physical Description
94 p.
application/pdf
Title Plain
Cathodic polarization behavior of mild steel exposed to selected flow velocities and slope parameters in natural seawater
Use and Reproduction
Copyright © is held by the author, with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
http://rightsstatements.org/vocab/InC/1.0/
Origin Information
1997
monographic
Boca Raton, Fla.
Florida Atlantic University
Physical Location
Florida Atlantic University Libraries
Place
Boca Raton, Fla.
Sub Location
Digital Library
Title
Cathodic polarization behavior of mild steel exposed to selected flow velocities and slope parameters in natural seawater
Other Title Info
Cathodic polarization behavior of mild steel exposed to selected flow velocities and slope parameters in natural seawater