Turbulent natural convection in a large rectangular cavity.
The thesis is part of a wider study of turbulent natural
convection in cavities undertaken by the U.K. Atomic Energy Authority,
to provide experimental data for the verification of computer codes
needed in the design of Fast Breeder Reactors. The objectives of the
present work were to design and construct a large rectangular air cavity
in order to measure distributions of temperature, velocity and local
heat transfer rates within the cavity.
The cavity was designed to operate with eitherisothermal hot
and cold walls, or a uniform heat flux hot wall and an isothermal cold
wall. These walls were 3m high and liii wide and the distance between them
(cavity thickness) was adjustable between .i.m and .5m. The horizontal
and vertical side walls were as nearly adiabatic as possible.
Temperature and velocity profiles were measured, at different
heights in the vertical mid-plane, with 25j.un diameter themocouples and
standard DISA hot-wire anemometer probes respectively. These measurements
were for isothermal walls and cavity thickness of .5m. The low
velocities and large temperature variations of the flow required a
special low speed jet to be designed and constructed for calibrating
the hot wires. The calibrations were for velocities up to l.Om/s at
temperatures between ambient and 70°C with the flow direction set
vertically upwards for the probe used near the hot wall and downwards
for the probe used near the cold wall.
The experimental data were recorded in digital form on magnetic
tapes, using a PDP/ll based data logging system. Statistical
analysis of these measurements, involving the local heat transfer
rates, mean and standard deviation of temperatures and velocities,
frequency spectra, etc. were later carried out on the QMC ICL 2980
The data are compared with results from other experiments
including some with a variety of different working fluids, and with
the predictions of available computer codes.