Thesis (MScIng)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: One of the areas of the fluid dynamic design of solar chimney power plants that has
not been investigated sufficiently is the collector-to-chimney transition section of a
single turbine layout. The transition section contains the turbine inlet guide vanes
(IGVs) that support the whole chimney and guide the flow entering the turbine. The
primary objective of the study was to determine the dependence of the loss coefficient
of the section on inlet guide vane stagger angle and collector roof height. Experiments
were done on a nominal 900 mm chimney diameter rig, with four combinations of
two collector roof heights and two IGV stagger angles. Velocity components and
pressures in the transition section were measured in three conical planes, respectively
at the IGV exit and midway to, and just below the turbine position, using a five-hole
pneumatic pressure probe. Very good agreement was found between experimental
values and commercial CFD code predictions of flow angles, velocity components
and internal and wall static pressures. The agreement between measured and predicted
total pressure loss coefficient was reasonable when considering that most of the loss
occurred in the weak wakes of the IGVs and in the very thin transition section wall
boundary layers. The CFD code served to extend the predictions to a proposed full
scale geometry. The losses are less than previously assumed. The study led to
correlations between respectively loss and turning angle as dependent variables, and
collector roof height and IGV stagger angle as independent variables. / AFRIKAANSE OPSOMMING: Een van die gebiede van vloeidinamiese ontwerp van sonskoorsteen kragstasies wat
nog nie voldoende navorsing geniet het nie is die kollektor-tot-skoorsteen oorgangs
gedeelte van `n enkel turbine opstelling. Die oorgangs gedeelte bevat die turbine se
inlaat lei lemme (ILL) wat die hele skoorsteen dra en die vloei lei wat by die turbine
ingaan. Die hoof doel van hierdie studie was om die verlies koëffisiënt van hierdie
oorgangs gedeelte te bepaal as afhanklike van die ILL stel hoek en die hoogte van die
kollektor se dak hoogte. Die eksperimente het op `n nominale 900mm deursnee
skoorsteen skaal model geskied, met vier kombinasies van twee dak hoogtes en twee
ILL stel hoeke. Snelheidskomponente en drukke is met `n pneumatiese 5-punt buis in
drie koniese vlakke in die oorgangs gedeelte gemeet. Die vlakke was by die ILL se
stert, halfpad deur die oorgangs gedeelte en by die turbine se inlaat. Baie goeie
ooreenstemming is gevind met die eksperimentele waardes en `n kommersiële CFD
kode se voorspellings van vloei hoeke, snelheidskomponente en interne- en wand
statiese drukke. Die ooreenstemming tussen die gemete waardes en die berekende
waardes vir die totale druk verlies koëffisiënt was redelik siende dat die meeste
verliese van die klein versteurings van die ILL en die oorgangs gedeelte se dun-wand
grenslae kom. Die CFD kode is toe ingespan om verdere voorspellings te maak vir `n
voorgestelde volskaal geometrie. Die verliese is minder as wat daar van te vore
voorspel is. Hierdie studie het gelei tot korrelasies tussen onderskeidelik verlies en
draai hoeke as afhanklike veranderlikes, en kollektor dak hoogte en ILL plasings hoek
as onafhanklike veranderlikes.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/21372 |
| Date | 12 1900 |
| Creators | Kirstein, Carl |
| Contributors | Von Backstrom, T. W., Kroger, D. G., Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xi, 96 leaves : ill. |
| Rights | Stellenbosch University |
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