Flow through a solar chimney power plant collector-to-chimney transition section

Kirstein, Carl (2004-12)

Thesis (MScIng)--University of Stellenbosch, 2004.

Thesis

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.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/21372
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