Optimization of fir-tree-type turbine blade roots using photoelasticity

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dc.contributor.advisor Endres, W.
dc.contributor.advisor Wettstein, H.
dc.contributor.author Hettasch, Georg
dc.contributor.other University of Stellenbosch. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. en_ZA
dc.date.accessioned 2010-05-25T07:15:37Z
dc.date.available 2010-05-25T07:15:37Z
dc.date.issued 1992-12
dc.identifier.uri http://hdl.handle.net/10019.1/993
dc.description Thesis (MEng.)-- University of Stellenbosch, 1992. 140 leaves on single pages, preliminary pages i-xi and numbered pages 1-113. Includes bibliography. Digitized at 600 dpi grayscale to pdf format (OCR),using an Bizhub 250 Konica Minolta Scanner and at 300 dpi grayscale to pdf format (OCR), using a Hp Scanjet 8250 Scanner. en_ZA
dc.description Thesis (MEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 1992
dc.description.abstract ENGLISH ABSTRACT: The large variety of turbo-machinery blade root geometries in use in industry prompted the question if a optimum geometry could be found. An optimum blade root was defined as a root with a practical geometry which, when loaded, returns the minimum fillet stress concentration factor. A literature survey on the subject provided guidelines but very little real data to work from. An initial optimization was carried out using a formula developed by Heywood to determine loaded projection fillet stresses. The method was found to produce unsatisfactory results, prompting a photoelastic investigation. This experimental optimization was conducted in two stages. A single tang defined load stage and a single tang in-rotor stage which modeled the practical situation. The defined load stage was undertaken in three phases. The first phase was a preliminary investigation, the second phase was a parameter optimization and the third phase was a geometric optimization based on a material utilization optimization. This material optimization approach produced good results. From these experiments a practical optimum geometry was defined. A mathematical model which predicts the fillet stress concentration factor for a given root geometry is presented. The effect of expanding the single tang optimum to a three tang root was examined. en_ZA
dc.description.abstract AFRIKAANSE OPSOMMING: Die groot verskeidenheid lemwortelgeometrieë wat in turbomasjiene gebruik word het die vraag na 'n optimum geometrie laat ontstaan. Vir hierdie ondersoek is 'n optimum geometrie gedefineer as 'n praktiese geometrie wat, as dit belas word, die mimimum vloeistukspanningskonsentrasiefaktor laat ontstaan. 'n Literatuur studie het riglyne aan die navorsing gegee maar het wynig spesifieke en bruikbare data opgelewer. Die eerste optimering is met die Heywood formule, wat vloeistukspannings in belaste projeksies bepaal, aangepak. Die metode het nie bevredigende resultate opgelewer nie. 'n Fotoelastiese ondersoek het die basis vir verdere optimeering gevorm. Hierdie eksperimentele optimering is in twee stappe onderneem. 'n Enkelhaak gedefineerde lasgedeelte en 'n enkelhaak in-rotor gedeelte het die praktiese situasie gemodeleer. Die gedefineerde lasgedeelte is in drie fases opgedeel. Die eerste fase was n voorlopige ondersoek. Die tweede fase was 'n parameter optimering. 'n Geometrie optimering gebasseer op 'n materiaal benuttings minimering het die derde fase uitgemaak. Die materiaal optimerings benadering het goeie resultate opgelewer. Vanuit hierdie eksperimente is 'n optimum praktiese geometrie bepaal. 'n Wiskundige model is ontwikkel, wat die vloeistukspanningskonsentrasiefaktor vir 'n gegewe wortelgeometrie voorspel. Die resultaat van 'n geometriese uitbreiding van die enkelhaaklemwortel na 'n driehaaklemwortel op die spanningsverdeling is ondersoek. af
dc.format.extent 130 leaves : ill.
dc.language.iso en en
dc.publisher Stellenbosch : University of Stellenbosch en
dc.subject Dissertations -- Mechanical engineering en
dc.subject Turbo-machinery en
dc.subject Blade root geometries en
dc.subject.lcsh Turbomachines -- Blades en
dc.subject.lcsh Blades -- Mathematical models en
dc.subject.lcsh Photoelasticity en
dc.title Optimization of fir-tree-type turbine blade roots using photoelasticity en
dc.type Thesis en
dc.rights.holder University of Stellenbosch en
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