Thesis (M.S.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains vii, 100 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 70-71).

The development and calibration of both a plane-headed (hemi-spherical view), and a spherical-type heat flux meter has been undertaken in this work. These instruments have been shown to be capable of producing a signal which is directly proportional to the incident radiant heat flux. Both radiant heat flux meters developed in this work, make use of a radial disc, conductivity type sensing element, where the incident radiant energy is distributed radially via the disc to a cooled metal block. The metal block heat sink is located at the end of a water-cooled arm to enable insertion into high temperature environments. Transient response analysis of the plane-headed heat flux meter yields a time constant of 10. 6 seconds. A perturbation analysis of the spherical heat flux meter concluded that the response time is a function of the radiation heat transfer coefficient existing between the probe and its environment. A finite difference analysis has been carried out on the radial disc assembly in order to investigate the temperature distribution under steady state conditions. It has been concluded that the mode of attachment of the radial disc assembly onto the cooling water probe, can have a modifying effect on the magnitude of the heat meter signal. However, this effect does not introduce non-linearity into the steady state signal response. For the finite difference analysis, an empirical correlation has been derived describing the convective heat transfer at a plane surface with the flow of cooling water perpendicular to the surface. The correlation applies for annular flow, and is given as: Nu = 1. 045 Re0. 4 Pr1/3 Testing of the spherical heat flow meter has been carried out in a 440kW gas-fired furnace. It has been concluded from these trials that: (i) a peak signal output is obtained for an equivalence ratio, o of between 1. 15 and 1. 32, in the range of firing rates 118kW to 142kW, where o is defined as. (ii) the ceramic shield, which forms an integral part of the heat meter, did not develop cracks or physical defects during the trials, (iii) the peak signal from the heat meter closely follows the peak heat gain by the furnace cooling water load rather than the optimum combustion conditions, as indicated by the flue gas composition. A steady state mathematical model of the gas-fired furnace is presented here, and is compared with the results obtained from the furnace runs. This is the first stage in the development of an unsteady state furnace model for use as an aid in the testing of furnace control systems.

M.Ing. / \Vith electrical power networks expanding beyond their original design limits and the various non-linear loads on the network, power quality has become an important issue in electrical engineering. Some of the largest non-linear loads on the power network are arc furnaces used to melt various metal orrs and scrap metal. In this study the focus is on fliCker as a power quality issue and more specifically the measurement and analysis methods of flicker at arc furnace installations. By measuring flicker and 3 phase voltage and current waveforms the effect of changes in arc furnace system parameters on flicker is determined. Various analysis methods based on statistical theory are described in this study. The aim is to gain a better understanding of flicker and arc furnaces to contribute to the current flicker knowledge base.

M.Ing. / The steelmaking process is briefly described with regard to process parameters and products influencing the fume extraction function of the water-cooled ducting. The flow distribution in the complex tubular network was determined by developing a software program based on parallel pass connections. A heat transfer analysis was performed on the specific problematic section referred to as the fixed elbow, with boundary conditions simulating the actual maximum operating conditions in an electric arc furnace. The temperature distribution was incorporated in a thermal stress analysis and a total stress profile was obtained for the radial as well as circumferencial positions. Areas of maximum stress were identified and the theory of fatigue failure due to cyclic operation was applied to these maximum stress conditions. The ABAQUS finite element program was used to model the behaviour of the material under the operating conditions using the sequencially coupled heat transfer and stress analysis routine. The results obtained correlates well with the actual failure of water-cooled ducting sections in operation and provides a platform for designing and optimising similar equipment for industrial applications.

M.Ing. / Steel products can be produced by either following the blast furnace with oxygen steel making route or the electric arc steel making route. The blast furnace with oxygen route requires liquid iron to produce steel and the electric arc route requires scrap metal as a major input. This in essence implies that for the blast furnace route if no liquid iron is produced, no steel products will be produced and similarly so for the electric arc route. ArcelorMittal Vanderbijlpark Works produces its liquid iron from two furnaces namely blast furnace C and blast furnace D. However the reliability of these furnaces is in question as their daily operations are plagued with random failures of equipment and machinery. The main consequence of these failures is the unavailability of the furnaces to produce liquid iron. This is undesirable from a business perspective due to the inherent production losses, loss of potential earnings as well as the high costs incurred to restore the furnaces back into operation.This research dissertation will focus on the operation of these blast furnaces. The fundamental success criteria for this research document will be to identify opportunities to improve the reliable operation of these furnaces. The scope of the work will however be limited to blast furnace C and particularly at improving its charging system’s availability. The availability of the charging system can be improved by knowing what type of failures to expect and how to mitigate their effects. A starting point would then be to examine past failure data. Thus data from 2008 has been collected and analyzed making use of statistical methods, design analysis methods and research methodologies. The results suggest that the availability of the system has a direct correlation between its reliability and maintainability. The results obtained were then subjected to a risk analysis to identify measures that could be employed to improve the charging system’s availability.

M.Phil. / Company XYZ is a marginal copper and nickel mine relying on emergency funding from the government in order to make it through difficult cash-flow periods. Previous change initiatives within the organisation have failed dismally. Changes within the organisation are however inevitable in order to prevent Company XYZ from closing down. This research proposes to study certain management philosophies and methodologies being used within Company XYZ, with a view to implementing change initiatives in order to ensure survival of the organisation. This was done by, comparing current management practices found in Company XYZ with literature. Topics include the direction in which the organisation is moving, the vision, management philosophies, reliability/quality and the restructuring of the organisation. A literature review of business process re-engineering was performed and a comparison to total quality management was made. Management philosophies were investigated and it is recommended that Company XYZ adopt Demings management philosophy as it focuses on quality, continuous improvement and employee involvement. Demings' 14 points were highlighted and the benefits were related to Company XYZ. The smelter is maintenance intensive and suffers from breakdown maintenance. As a result, it is recommended that reliability centred maintenance principles are implemented. Company XYZ further need to introduce design review meetings in order to improve the quality in which modifications are implemented. Along with business process re-engineering, four organisational designs were investigated, i.e. the functional organisation, the product organisation, the matrix organisation and the network organisation. Due to the size and complexity of the organisation and the need to focus on business objectives, it is recommended that Company XYZ adopt the network organisational structure and it is further recommended that the smelter focus on processes. Therefore the smelter is to be viewed as a business unit and based on the advice of BPR practitioners it is recommended that the smelter focus on processes. In order to ensure that the proposed changes are implemented successfully, the issue of change management and the importance thereof was investigated. Factors that can affect the change process were highlighted.

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The influence of coking conditions, with respect to position in a commercial coke-oven, on the mechanical behaviour of blast furnace coke has been studied. This involved the determination of density, porosity, the characterization of microstructure and assessing the influence of all three on the compressive strength of coke. The plastic flow properties were also investigated at temperatures greater than 1000°C. Three coke batches, originating in a 5m commercial coke-oven at three different positions with respect to height (0.8m, 3.3m and 5m below the coal line), along with three coke batches produced in a 460mm test-oven, were supplied by Energy, Mines and Resources (CANMET) in Ottawa. A warf coke batch was also provided as a control sample. Several hundred core-drilled specimens (≃1.3cm diameter and 1.3cm length) were produced from the seven coke batches. The bulk density of each cylindrical coke specimen was determined. Also, a detailed microstructural analysis, using a Leitz Image Analyzer, of the flat faces of the coke cylinders was performed to quantitatively characterize the pore and cell wall size, and the pore geometry. The compressive strength of each coke cylinder was determined both at ambient temperature and at 1400°C. In addition, the plastic flow behaviour of the commercially produced coke batches was studied. Results indicate that the coke product bulk density was affected by the coke-oven pressure (static load). Studies of the test-oven coke batches revealed that coke bulk density increased with higher oven pressure. Furthermore, the pore size was found to be larger for cokes produced at lower oven pressures. The cell wall size did not appear to be affected by coke-oven pressure. The bulk density of the commercially produced samples increased with depth below the coal line. This was attributed to a higher temperature and static load that existed at the bottom of the battery. The pore size was larger in cokes extracted from higher regions. No correlation of cell wall size with depth below the coal line was found. However, an oven size effect on the pore and wall size was noticed. Both the pore and wall size was smaller in the test-oven coke batches. The compressive strength of coke was higher in batches subjected to higher coke-oven pressures. Similarly,' the compressive strength of commercial coke batches was higher for coke batches extracted from regions near the sole of the coke-oven, than that for coke batches extracted from higher regions. It was concluded that high oven pressures resulted in cokes exhibiting a lower porosity and small pores which had the combined effect of producing stronger coke. Coke strength was generally shown to be higher at 1400°C than at room temperature. The test-oven cokes were always stronger than cokes produced in the 5m commercial coke-oven. Constant load tests revealed that coke exhibited plastic flow behaviour at temperatures above 1000°C. The time dependent strain data was described using an interactive-double-Kelvin element visco-elastic model. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

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