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Implementation of high-lift devices on axial flow fans.
Thesis (MEng)--Stellenbosch University, 2021.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2021
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| _version_ | 1867614037092597760 |
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| access_status_str | Open Access |
| author | Herbst, C. I. |
| author2 | Meyer, C. J. |
| author_browse | Herbst, C. I. Meyer, C. J. |
| author_facet | Meyer, C. J. Herbst, C. I. |
| author_sort | Herbst, C. I. |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/123602 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:45:40.057Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/123602 Implementation of high-lift devices on axial flow fans. Herbst, C. I. Meyer, C. J. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Gurney Flap High-Lift Axial flow -- Fans (Machinery) Fans (Machinery) -- Design UCTD Air-cooled condensor Thesis (MEng)--Stellenbosch University, 2021. ENGLISH ABSTRACT: Axial flow fans are used in large air-cooled condensors (ACCs) for thermal power plants. These fans are used to force air through heat exchanger bundles. The advantage of thermal plants equipped with ACCs is that they do not require large volumes of water. A study by Bruneau (1994) at the University of Stellenbosch resulted in the B2-fan. This fan has shown improved performance at design as well as off-design condi- tions. Bruneau’s design methodology incorporates a free vortex design. With re- cent trends in industry of low pressure rise, high-volume flow rate fans, Bruneau’s methodology results in large chord lengths and excessive blade twist at the root. This study aimed to adapt the design methodology to include the use of a high-lift device, a gurney flap (GF), to reduce the blade’s root chord. The adapted design procedure was used to design and manufacture the C-fan. The C-fan features a 15 % reduction in the root chord length of the blade. The C-fan was able to meet the required performance specifications as outlined in the design. A numerical investigation into the Eppler 420 airfoil with and without a GF was done to determine it’s lift and drag coefficients to be used in the design procedure. The Eppler 420 airfoil was used in conjunction with the Nasa LS413 airfoil, which was used for the outer section of the blade. The C-fan was numerically investigated using the actuator disk model (ADM). The ADM predicts a higher fan static efficiency (46 %) than what was achieved with experimental fan tests (42.5 %). Poor building quality, thick trailing edges and rough GF’s all attributed to the C-fan’s under performance in terms of effi- ciency. Based on the results of the C-fan it is recommended to improve the manufactur- ing process to produce blades of better quality. This will ensure that the C-fan’s efficiency be improved to match the ADM efficiency prediction more closely. It is also suggested that the transition zone between the Eppler 420 airfoil and the Nasa LS413 airfoil be investigated either numerically or experimentally to reduce the uncertainty in prediction of the ADM. AFRIKAANSE OPSOMMIMG: Aksiale vloei waaiers word in groot lugverkoelde kondensors (LVKs) vir termiese kragsentrales gebruik. Hierdie waaiers word gebruik om lug deur warmtewisselaar- bundels te dwing. Die voordeel van termiese aanlegte wat met LVKs toegerus is, is dat hulle nie groot hoeveelhede water benodig nie. ’n Studie deur Bruneau (1994) aan die Universiteit van Stellenbosch het die B2- waaier tot gevolg gehad. Hierdie waaier het verbeterde prestasie getoon tydens ontwerp sowel as buite ontwerps-toestande. Bruneau (1994) se ontwerpsmetodiek bestaan uit ’n vrye vorteks ontwerp. Met onlangse tendense in die industrie van lae drukverhoging, hoë-volume vloeitempo-waaiers, lei Bruneau (1994) se metodologie tot groot koordlengtes en oormatige lemdraai aan die naaf. Hierdie studie het ten doel gehad om die ontwerpsmetodologie aan te pas sodat dit die gebruik van ’n hoë-lig toestel, ’n gurney flap (GF), insluit om die koordlengte aan die naaf te verminder. Die aangepaste ontwerpprosedure is gebruik om die C-waaier te ontwerp en te vervaardig. Die C-waaier het ’n afname van 15 % in die lengte van die koord by die naaf. Die C-waaier kon voldoen aan die vereiste spesifikasies soos uiteengesit in die ontwerp. ’n Numeriese ondersoek van die Eppler 420 profiel met en sonder ’n GF is gedoen om die hef- en sleurkoëffisiënte wat gebruik moet word in die ontwerpprosedure te bepaal. Die Eppler 420 profiel is in kombinasie met die Nasa LS413-profiel gebruik. Die Nasa LS413-profiel is in die buitenste gedeelte van die lem gebruik. Die C-waaier is numeries ondersoek met behulp van die aksieskyf model (ASM). Die ASM voorspel ’n hoër statiese doeltreffendheid (46 %) as wat met eksperimen- tele waaiertoetse bereik is (42.5 %). Swak boukwaliteit, dik sterte en ruwe GF’s word toegeskryf aan die C-waaier se onderprestasie ten opsigte van doeltreffend- heid. Op grond van die resultate van die C-waaier word daar aanbeveel om die ver- vaardigingsproses te verbeter om lemme van beter gehalte te vervaardig. Dit sal verseker dat die doeltreffendheid van die C-waaier verbeter word om nader aan die ASM-doeltreffendheidsvoorspelling te wees. Daar word ook voorgestel dat die oorgangsone tussen die Eppler 420 profiel en die Nasa LS413 profiel numeries of eksperimenteel ondersoek word om die onsekerheid in die voorspelling van die ASM te verminder. Masters 2021-06-23T14:52:02Z 2021-12-22T14:11:41Z 2021-06-23T14:52:02Z 2021-12-22T14:11:41Z 2021-12 Thesis http://hdl.handle.net/10019.1/123602 en_ZA Stellenbosch University 124 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Gurney Flap High-Lift Axial flow -- Fans (Machinery) Fans (Machinery) -- Design UCTD Air-cooled condensor Herbst, C. I. Implementation of high-lift devices on axial flow fans. |
| title | Implementation of high-lift devices on axial flow fans. |
| title_full | Implementation of high-lift devices on axial flow fans. |
| title_fullStr | Implementation of high-lift devices on axial flow fans. |
| title_full_unstemmed | Implementation of high-lift devices on axial flow fans. |
| title_short | Implementation of high-lift devices on axial flow fans. |
| title_sort | implementation of high lift devices on axial flow fans |
| topic | Gurney Flap High-Lift Axial flow -- Fans (Machinery) Fans (Machinery) -- Design UCTD Air-cooled condensor |
| url | http://hdl.handle.net/10019.1/123602 |
| work_keys_str_mv | AT herbstci implementationofhighliftdevicesonaxialflowfans |