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ANP PROJECT QUARTERLY PIJQGRESS REPORT
13. HEAT TRANSFER AND PHYSICAL PROPERTIES RESEARCH
H. F. Poppendiek, Reactor ExperimenLal Engineering Division
'The thermal conductivity of the
fluoride mixture NaF-BeF2 (57-43 mole
%) was experimentally determined to
be 2.4 Btu/hr*ft."F over a temperaturr
range of 452 to 586°C. This result
is comparable with the thermal con-
ductivi ties previously obtained for
some of the other fluoride mixtures.
Two new thermal conductivity devices
have been developed and successfully
tested with ordinary liquids.
The enthalpies and heat capacities
of fuel mixture NaF-KF-ZrF,-UF,
(4.8-50.1-41.3-3.8 mole %) have been
obtained. The heat capacity can be
represented by c = 0.28 +_ 0.015
P
cal/cm."C over the temperature range
540 to 900°C.
The viscosities and densities of
the fluoride mixtures NaF-ZrF, (50-50
mole 760) and NaF-ZrF,-UF, (50-25-25
mole 7%) have been measured with the
modified Brookfield viscometer. The
viscosity of the first mixture ranged
from 15 cp at 610°C to 5 cp at 1030°C.
The viscosity of the second mixture
ranged from 20 cp at 650°C to 11 cp
at 880°C. These results are compared
w i t X the viscosity measurements
previously determined for some of the
0 ther fluoride mix tures. Development
of the capillary viscometer is conti
nuing.
The vapor pressure of NaZrF, increases
from 8 mm Hg at 800°C to 30
mm Hg at 900°C; this behavior is
similar to that previously reported
for the NaF-ZrF,-UF, (50-46-4 mole X)
mixture. Experimental values of the
vapor pressure of BeF2 measured at
RMI agreed with values calculated at
ORNL .
Preliminary experiment a1 heat
transfer coefficients have been
pbtained for the case of turbulently
flowing NaF-KF-LiF mixture in a long
tube. It appears that heat transfer
with this mixture can probably be
described by the usual forced-convection
174
expressions characterizing ordinary
fluids, as was found to be the case
for mol ten sodium hydroxide.
Sever a1 thermal analyses pertaining
to the reflector-moderated reactor
have been conducted. One study was
made concerning the heat generation
within the reflector and shell of the
reactor. Another analysis consisted
of preparing design charts for cooling-
hole distributions in reactor re-
flectors. An attempt to minimize the
weight and volume of air radiators
has been initiated.
A pyrex thermal convection harp
has been designed and constructed for
an experimental inquiry into harp
convection velocities. The experi-
mental dat,a are to be used to check
the validity of analytical methods
used to predict the circulation
velocities.
An investigation has been initiated
in an attempt to derive a heat-momentum
transfer analogy for the annulus in
much the same way as it has been
derived for the pipe system.
An experiment has been designed
that w i l l make possible an experimental
study of the heat transfer chasac-
teristics of a simple, fuel-circulating
system; a long pipe w i l l be used in
which the flowing fluid is heated
internally by an electric current.
The experimental results w i l l be
compared with the previously obtained
theoretical results.
THERMAL CONDUCTIVITY OF LIQUIDS
W. D. Powers R. M. Burnett
S. J. Claiborne W. 8. Harrison
Reactor Experiment a1 Engineering
Division
A thermal conductivity deiice
similar to the one described previ-
ously(') was used to study the fluoride
(l)L. F. Basel end M. Tobias, ANP Quar. Prog.
Rep. Dec. 10. 1950. ORNL-919, p. 196.