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A water bath thermal Processor was designed and built to study the influence of helical coil characteristics on heat transfer to Newtonian fluids like water and base oil with three different viscosities. The system consisted of a thermally insulated water bath, an electric heater, pump to re-circulate water in the bath and for pumping the processing fluid through the coil, copper helical coils and a storage tank for the processing fluid. / Comparative study has shown that the outer and total heat transfer coefficients were significantly lower in natural than in forced convection water bath. However, inner heat transfer coefficient was not significantly affected. Flow rate as low as 0.001 m.s-1 in the water bath improved the outer and total heat transfer coefficients by 35 and 22% respectively. One could expect a higher rate with an increase in water re-circulation rate inside the water bath. Percent rise in heat transfer was limited to seven with respect to inner heat transfer. With the Pearson correlation, it was possible to express total heat transfer rate directly in terms of outer and inner rates. Significant interactions were observed between variables and constants. / Experiments with 2 pitch cases were conducted with water to water heat transfer using coils to determine the Nusselt number correlation for natural convection. Characteristic lengths were changed in the models. The Nusselt number was under-predicted by 25 to 37% for water bath temperatures of 75° and 95°C respectively. Flow rate inside the coil had slight effect on Nusselt number due to change in the temperature gradient along the length of the coil. / Studies conducted with three base oils have shown significant difference in viscosity after heating the oil for several turns. Each fluid was heated in a distinct flow regime. The observed Nusselt number inside the coil for low Reynolds number was as high as an order of magnitude than the predicted values calculated by Seider-Tate relation for laminar flow. Vorticies formed associated with the eddy structure could very well be the cause for this kind of rise in the value. / Preliminary study conducted has shown a higher rise in temperature of processing fluid in case of helical coil compared to that of a straight tube. Larger the diameter of the tube better was the heat transfer. An elevated bath temperature had higher heat transfer.

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The radiation heat transfer from an argon and a nitrogen transferred-arc column to a cylindrical enclosure was measured. The rate of heat transfer was successfully correlated in a non-dimensional manner, with respect to the arc length within the enclosure and the enclosure diameter for the section of the arc column located within the enclosure, and with respect to the arc length outside the enclosure and the enclosure diameter for the section of the arc column outside the enclosure. / It was discovered that tangential injection of a particulate feed material into the cylindrical enclosure led to the formation of destabilizing lump-like deposits on the roof and wall of the enclosure. Feeding vertically through the roof of the enclosure in the presence of a vortex resulted in the formation of a uniform film deposit and stable operation. Under these conditions, up to 49% of the incident radiant energy emanating from the arc column to the sleeve surface was absorbed by the feed. / The carbothermic reduction of a fine (3-10$ mu$m) V$ sb2$O$ sb5$ powder in the plasma furnace resulted in the production of a commercial ferrovanadium alloy of controllable vanadium content. Particulate losses to the exhaust gases were very low, in the order of 2%. Specific energy consumption was 17kWh/kg of vanadium produced. Based on the results of these tests, specific energy consumption at a larger scale would be reduced by at least 50%.

An experimental and numerical study of he aerodynamics and the associated heat transfer on turbine blades, has been carried out as part of the ongoing Armscor Denel aircraft engine maintenance program. The experimental tests were performed using an existing continuous flow cascade test facility at the University of KwaZulu-Natal, Durban. These experimental results were used to validate the two-dimensional numerical results, generated usmg a commercially available Computational Fluid Dynamics (CFD) package, FLUENT. The existing experimental turbine test facility utilises a continuous flow cascade technique where a cooled, instrumented blade is rapidly introduced to the hot-air stream exposing it to the cascade flow. This creates the heat transient required for measurement of the isothermal heat transfer coefficients, using thin-film heat flux gauges. A static pressure test blade is used in conjunction with a scanivalve system, to determine the blade mid-span pressure distribution. This latest research effort requires validation of de Villiers' [2002] results, whilst improving the error discrepancies between the experimental and numerical analyses. Maintenance on the test rig has been performed, including the addition of a new pressure control system to ensure the correct cascade flow conditions and boundary conditions are obtained. Experimental pressure distribution measurements were performed, to validate previous work by de Villiers [2002] and to ensure the correct operation of the test rig. Experimental error was identified in de Villiers' [2002] suction surface pressure distribution, and new experimental pressure results were acquired. Following the essential overhaul of critical rig components, experimental heat transfer tests were performed. The newly restored equipment produced new isothermal heat transfer coefficient results that validated the results of de Villiers' [2002]. Numerous CFD meshing techniques were investigated and implemented in FLUENT, to produce the numerical solution. The pressure correlation proved to be excellent with an average error of 3%. The varying cascade inlet turbulence intensity was identified as a major source of heat transfer error. Implementing this variance into FLUENT, a significant reduction in error was seen. The resulting average heat transfer error measured 12%, a major improvement from 29% error in 2002. / Thesis (M.Sc.Eng.)-University of Kwazulu-Natal, 2007.

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