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 computer. 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.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:307545 |
| Date | January 1993 |
| Creators | Ziai, Said |
| Publisher | University of London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.0018 seconds