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No description available.

Thesis (MTech(Electrical Engineering))--Cape Technikon, Cape Town,1995 / This thesis describes the research, development and design of one of the most modern generic control and automation system for mini Hydro turbines available in the world. Special emphasis is placed on the Man machine interface. A concept of total dynamic plant and data status representation was pursued. To achieve this, a large amount of graphical animation was incorporated into the design. The end product was to be the most economical and cost effective implementable design available , yet providing the most modern functions and features available in the world market. The system was developed and researched to be generic and applicable to any small Hydro plant. The design can thus be implemented on any suitable PLC and SCADA system and is not dependant on any specific manufactures hardware or software. The main emphasis is laid on functional capability of the design. Utilising this design standard would virtually cut the cost of engineering associated with the design of a Hydro control system by 90%. The design and engineering costs related to a Hydro automation project could typically exceed R 100 000 a for small Hydro plant as this scheme.

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Microfiche copy available in Archives and Engineering. / Bibliography: leaf 149. / M.S.

This thesis presents and examines the concept that the output of a wound-rotor induction generator (WRIG) can be limited by means of linking to external impedances for wind-turbine generating system application. An 80kW-WRIG is simulated as a model to examine the control of the output power vs. speed characteristic. Model of WRIG derived from per phase equivalent circuit is organized, then it is estimated how much external impedances affect the characteristic of output power for it to approach to a typical wind-turbine curve. Practical tests are performed using 80kW-WRIG in testing lab to validate the simulation data. In addition, a smaller WRIG, connected on same shaft as 80kW-WRIG, is designed to extend the range of wind speed. Also external impedances with smaller WRIG are chosen to extract optimum power from wind-turbine. Finally, passively controlled tandem WRIGs are shown to have the capability to optimize wind-turbine energy extraction when controlled entirely by external impedances. / Graduation date: 2003

No description available.

M.S.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The main components of a micro gas turbine engine are a centrifugal or mixed-flow compressor, a combustion chamber and a single stage axial-flow or radial-flow turbine. The goal of this thesis is to formulate a design methodology for small axial-flow turbines. This goal is pursued by developing five design-related capabilities and applying them to develop a turbine for an existing micro gas turbine engine. Firstly, a reverse engineering procedure for producing digital three-dimensional models of existing turbines is developed. Secondly, a procedure for generating candidate turbine designs from performance requirement information is presented. The third capability is to use independent analysis procedures to analyse the performance of a turbine design. The fourth capability is to perform structural analysis to investigate the behavior of a turbine design under static and dynamic loading. Lastly, a manufacturing process for prototypes of a feasible turbine design is developed. The reverse engineering procedure employs point cloud data from a coordinate measuring machine and a CT-scanner to generate a three-dimensional model of the turbine in an existing micro gas turbine engine. The design generation capability is used to design three new turbines to match the performance of the turbine in the existing micro gas turbine engine. Independent empirical and numerical turbine performance analysis procedures are developed. They are applied to the four turbine designs and, for the new turbine designs, the predicted efficiency values differ by less than 5% between the two procedures. A finite element analysis is used to show that the stresses in the roots of the turbine rotor blades are sufficiently low and that the dominant excitation frequencies do not approach any of the blade natural frequencies. Finally prototypes of the three new turbine designs are manufactured through an investment casting process. Patterns made of an organic wax-like material and a polystyrene material are used, with the former yielding superior results. / AFRIKAANSE OPSOMMING: Mikro-gasturbiene-enjins bestaan uit 'n sentrifugaal- of ‘n gemende-vloeikompressor, 'n verbrandingsruim en 'n enkel-stadium-aksiaalvloei- of ‘n radiaalvloei-turbine. Die doel van hierdie tesis is om 'n ontwerpsmetodologie vir klein aksiaalvloei-turbines saam te stel. Hierdie doel word deur die ontwikkeling en toepassing van vyf ontwerpsverwante vermoëns nagestreef. Eerstens word 'n tru-waartse-ingenieursproses ontwikkel om drie-dimensionele rekenaarmodelle van die bestaande turbines te skep. Tweedens word 'n metode om kandidaatturbineontwerpe vanaf werkverrigtingsvereistes te verkry, voorgestel. Die derde ontwerpsvermoë is om die werksverrigting van 'n turbineontwerp met onafhanklike analises te evalueer. Die vierde ontwerpsvermoë is om die struktuur van 'n turbinelem te analiseer sodat die effek van statiese en dinamiese belastings ondersoek kan word. Laastens word 'n vervaardigingsproses vir prototipes van geskikte turbineontwerpe ontwikkel. Die tru-waartse-ingenieursproses maak gebruik van 'n koördinaat-meet-masjien en 'n CT-skandeerder om puntewolkdata vanaf die turbine in 'n bestaande mikro-gasturbiene-enjin te verkry. Die data word dan gebruik om 'n drie-dimensionele model van die turbine te skep. Die ontwerpskeppingsvermoë word dan gebruik om drie kandidaatturbineontwerpe vir die bestaande mikro-gasturbiene-enjin te skep. Onafhanklike empiriese en numeriese prosedures om die werkverrigting van 'n turbineontwerp te analiseer word ontwikkel. Beide prosedures word op die vier turbineontwerpe toegepas. Daar word gevind dat die voorspelde benuttingsgraadwaardes van die nuwe ontwerpe met minder as 5% verskil vir die twee prosedures. 'n Eindige-element-analise word dan gebruik om te wys dat die spannings in die wortels van die turbinelemme laag genoeg is, asook dat die dominante opwekkingsfrekwensies nie die lem se natuurlike frekwensies nader nie. Laastens word prototipes van die drie nuwe turbineontwerpe deur 'n beleggingsgietproses vervaardig. In die vervaardigingproses word die effektiwiteit van twee materiale vir die gietpatrone getoets, naamlik 'n organiese wasagtige materiaal en 'n polistireen-materiaal. Daar word bevind dat die gebruik van die wasagtige gietpatrone tot beter resultate lei.