ORNL-2106 - the Molten Salt Energy Technologies Web Site

THERMAL CONDUCTIVITY
W. D. Powers
Two new devices have been built that are being
used to determine the conductivities of liquids.
In both systems a measured amount of heat flows
down through a horizontal sample of known thick-
ness and area. The thickness of the sample may
be varied so that contact resistances at the
surfaces of the sample can be eliminated.
One device has been fabricated in which the
sample is contained within glass. This makes it
possible to observe whether any gas bubbles
or films are present in the cell at the time measure-
ments are being made. Good agreement with the
known thermal-conductivity data for water was
obtained. Initial experiments with heat-transfer
salts have shown the formation of gas bubbles on
the surfaces. The effect of this gas on the thermal
conductivity is currently being studied.
One of the difficulties associated with the
measurement of thermal conductivity is in knowing
PERIOD ENDING JUNE 10, 1956
exactly where the heat is flowing. The second
device has two heat meters, one directly above
and the other directly below the sample. It was
assumed that if the heat flow were the same
in both meters, the heat flow through the sample
would be well established. The original design
did not meet this specification and therefore a
modification of the system is now being made.
ELECTRICAL CONDUCTIVITY
N. D. Greene
An electrical conductivity cell has been standard-
ized at high temperatures with molten potassium
chloride, and the cell constant so obtained agreed
within experimental error with those determined
by means of standard, aqueous solutions. Further
cell standardization with molten NaCl and ZnCI,,
as well as refinements of existing measuring
techniques, will precede measurements of the
conductivities of fluoride melts.
233