ORNL-1816 - the Molten Salt Energy Technologies Web Site

a much smaller area was obscured by the grid
7 I ines themselves. Inherent difficulties have beset
attempts to measure the settling velocity of the
c
particles; however, it can be said that the terminal
velocity of free fall of Lycopodium spores in water
under gravity is certainly less than 0.2 cm/sec
and probably much less. Even this is only about
m
0.16% of the mean velocity which will be measured.
.
The Hewlett-Packard counter which measures the
time interval between flashes was adiusted; its
absolute accuracy was checked; and it was found
to be satisfactory.
The design of another entrance section which
a will impart a rotational component of velocity to
s
the fluid as it flows through the test section has
been started. This will produce a velocity structure
which is more realistic in terms of what is
envisaged for the ART, but it is much more
difficult to measure. It is conceivable that a
rotational component will help to reduce the
possible adverse thermal effect of separation
; =
regions, perhaps by el iminating these regions.
The velocity distribution in a diverging channel
under turbulent flow conditions was studied with
9:
the phosphorescent-particle technique. Flow
I
-
*
L
asymmetry at a half-angle of 4 deg was observed.
This angle is somewhat less than the 5-deg halfangle
given in the classical report on velocity
*
profiles in channels by Nikurad~e.~ A large flowvisualization
system that utilizes the phosphorescent
particle and dye techniques for studying
fluid flow characteristics has nearly been com-
pleted.
PERIOD ENDING DECEMBER 10,1954
volume heat sources within the fluids of experi-
mental forced-flow volume-heat-source systems.
An experimental study of the factors affecting
gas formation at an electrode-electrolyte interface
was carried out pursuant to the problem cf gener-
ating volume heat sources electrically. The
generation of gas at an electrode was found to
be dependent upon the material of the electrode
and the current density and independeni of the
applied potential, as well as the type of electro-
lyte employed. Platinum was found to have the
most desirable characteristic of conducting the
maximum amount of current per unit area of elec-
trode to an electrolyte for a given degree of gas
generation. This effect is most probably the
result of an increased surface area because of
the known porosity of this metal. For brightly
polished platinum, a current density of approxi-
mately 8 amp/in.2 was achieved before g(is liber-
ation was noticeable. This value exceeded that
of Carpenter 20 stainless steel by two orders of
magnitude. Also, tests were carried out to study
the compatibility of the more common stainless
steels and dilute solutions of strong electrolytes
in those portions of an experimental volume-heat-
source system where no electric currents are
flowing. Carpenter 20, type 347, and type 316
stainless steels were found to be accordant.
Concomitant with the problem of generating
uniform volume heat sources within aiinuli of
nonuniform cross section, a method for embedding
platinum electrodes to form a hydrodynomically
smooth surface has been developed. It has been
established that several of the new epoxy bonding
plastics adhere to suitably roughened metals in
such a manner that the castins of composite