IGCAR : Annual Report - Indira Gandhi Centre for Atomic Research

IGC
Annual Report 2007
expected in this row. Hence the
optimum position of the
thermocouple tip determined
for this location will be
conservative for the other inner
rows. Hot water (≈ 338 K) was
sent through one SA, whereas
in the rest of the core, cold
water was circulated. The
attenuation of temperature at
this thermocouple tip location
by the neighbouring SAs was
studied. A retractable
thermocouple was inserted in
this location from the CP top as
shown in Fig.1. The height of
the thermocouple tip above
core top can be varied by
traversing the thermocouple
from CP top. From the
statistical analysis of data the
mean temperature as seen by
each thermocouple was
estimated. These temperature
data are presented in a
normalized form to transpose
the result into reactor case by
substituting the prototype
parameters. The normalization
is done in the following
manner.
where,
T = Mean temperature of the
fluid as measured by the
thermocouple mounted in CP
T h = Mean temperature of the
hot inlet fluid (Thermocouple
mounted at the SA exit)
Tc
= Mean temperature of
the cold inlet fluid
(Thermocouple mounted at the
SA exit)
The normalized mean
temperature ( )is
plotted against the elevation of
the thermocouple tip above
core top for various
experimental conditions. The
result is presented Fig. 2. It can
be seen from the above figure
that normalized mean
temperature is close to unity
(which means the fluid
temperature as measured by
the thermocouple is almost
equal to the SA exit
temperature) at the core
temperature monitoring point
upto the height of 34 mm
above core top in model and
then it decreases gradually
along the jet axis due to the
increased mixing of the liquid
streams. The corresponding
height of the thermocouple tip
in reactor is 136 mm (because
the geometric scale of the
model is 1:4). The normalized
mean temperature is also
independent of Re upto this tip
elevation above core top.
Fig.2 Variation in mean temperature along the jet axis (in model)
ENABLING TECHNOLOGIES 127