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Reynolds number scaling in 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_ | 1867613994552918016 |
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| access_status_str | Open Access |
| author | Steenkamp, G. M. |
| author2 | Meyer, C. J. |
| author_browse | Meyer, C. J. Steenkamp, G. M. |
| author_facet | Meyer, C. J. Steenkamp, G. M. |
| author_sort | Steenkamp, G. M. |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/123868 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:59.428Z |
| 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:10019.1/123868 Reynolds number scaling in axial flow fans. Steenkamp, G. M. Meyer, C. J. Van der Spuy, S. J. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Axial flow -- Fans (Machinery) Turbulence Reynolds number UCTD Thesis (MEng)--Stellenbosch University, 2021. ENGLISH ABSTRACT: There exists uncertainty about the accuracy with which the fan scaling laws can predict the performance characteristics of a full scale prototype fan from model testing. This uncertainty stems from the large difference in Reynolds number that typically exists between the prototype and model fan. Increasing the turbulence intensity of the inlet flow during testing of the model fan is a suggested method for improving Reynolds number similarity between the two scenarios. The similarity between increasing the turbulence intensity of the flow and in- creasing the Reynolds number is demonstrated through experimental testing of the NASA LS 0413 aerofoil of McGhee and Beasley (1975). For this purpose, the aerofoil testing system of Herbst (2021) is modified and improved. The aerofoil testing system was shown to accurately and repeatably predict the lift coefficient of the NASA LS 0413 aerofoil. The prediction of the drag coefficient showed poor repeatability, however, results equivalent to that of McGhee et al. (1977) was still achieved at lower angle of attacks. The increased levels of turbulence intensity in the flow was achieved through the use of passive grids placed upstream of the aerofoil. Following on the single aerofoil experiments, experimental testing of the M- fan developed by (Wilkinson, 2017) was conducted with increased levels of inlet flow turbulence intensity, thus mimicking higher Reynolds number operation. The increase in turbulence intensity had no effect on the performance of the M-fan operating at its design conditions, with the results being within the relative stan- dard deviation (RSD) of repeatability for the test system. This correlates to RSD values less than 0.664 % for fan static pressure, 1.30 % for fan static efficiency and 0.903 % for fan power. It is therefore concluded that scale model testing of the M-fan should yield accurate results when scaled to represent the performance characteristics of a full scale prototype. This experimental method is also vali- dated through the Reynolds number effect obtained when testing the M-fan at a very high blade setting angle of ζ = 40◦, resulting in a maximum increase in fan static efficiency of 1.81%. AFRIKAANSE OPSOMMING: Daar bestaan onsekerheid oor die akuraatheid waarmee die waaier skaleringswette die werksverigting van ’n volskaal prototipe waaier kan voorspel. Hierdie onseker- heid is gebasseer op die tipiese groot verskil tussen die Reynoldsgetalle van ’n model en prototipe waaier. Verhoogde vlakke van inlaatvloei turbulensie intensiteit is ’n voorgestelde metode vir die verbetering van Reynoldsgetal ooreenstemming. Die ooreenkomste tussen die verhoging van die turbulensie intensiteit van die inlaat vloei tydens die toets van ’n waaier en die verhoging in Reynoldsgetal is be- vestig deur eksperimentele toetse op die NASA LS 0413 vlerkprofiel van McGhee en Beasley (1975). Veranderinge en verbeteringe aan die vlerkprofiel toetsstelsel van Herbst (2021) is gemaak vir die doel. Die hefkragkoeffisient van die NASA LS 0413 vlerkprofiel kon akkuraat en met goeie herhaalbaarheid gemeet word met die vlerkprofiel toetsstelsel. Die voorspelling van die sleurkragkoeffisient toon egter swak herhaalbaarheid. Desnieteenstaande was die toetse instaat om soortgelyke resultate as McGhee et al. (1977) te verkry by lae aanvalshoeke. Die verhoogde vlakke van turbulensie intensiteit in die inlaat vloei was bewerkstellig deur die gebruik van statiese roosters wat stroomop van die vlerkprofiel geplaas was. Na afloop van die twee-dimensionele vlerkprofiel toetse, is eksperimentele toetse op die M-waaier (Wilkinson, 2017) uitgevoer met verhoogde vlakke van turbulensie intensiteit in die inlaatvloei om ’n hoër Reynoldsgetal na te maak. Die verhoging van die turbulensie intensiteit het geen invloed gehad op die werksverigting van die M-waaier by sy ontwerpstoestande nie, met resultate wat binne die relatiewe standaardafwyking (RSA) van die toetstelsel val. Die korrelerende RSA waardes is minder as 0.664 % vir waaier statiese druk, 1.30 % vir waaier benuttingsgraad en 0.903 % vir waaier drywing. Daar kan dus tot die slot gekom word dat skaalmo- del toetse van die M-waaier akurate resultate sal lewer wanneer die toetsresultate geskaleer word om die werksverigting van die volskaal prototipe waaier te ver- teenwoordig. Die geldigheid van hierdie eksperiment is addisioneel bevestig deur die waargenome Reynoldsgetal effek wanneer die M-waaier getoets word teen ’n baie hoë lem stel hoek van ζ = 40◦, waar ’n maksimum verhoging van 1.81 % waargeneem word vir waaier benuttingsgraad. Masters 2021-11-30T21:16:33Z 2021-12-22T14:26:05Z 2021-11-30T21:16:33Z 2021-12-22T14:26:05Z 2021-12 Thesis http://hdl.handle.net/10019.1/123868 en_ZA Stellenbosch University 128 pages application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Axial flow -- Fans (Machinery) Turbulence Reynolds number UCTD Steenkamp, G. M. Reynolds number scaling in axial flow fans. |
| title | Reynolds number scaling in axial flow fans. |
| title_full | Reynolds number scaling in axial flow fans. |
| title_fullStr | Reynolds number scaling in axial flow fans. |
| title_full_unstemmed | Reynolds number scaling in axial flow fans. |
| title_short | Reynolds number scaling in axial flow fans. |
| title_sort | reynolds number scaling in axial flow fans |
| topic | Axial flow -- Fans (Machinery) Turbulence Reynolds number UCTD |
| url | http://hdl.handle.net/10019.1/123868 |
| work_keys_str_mv | AT steenkampgm reynoldsnumberscalinginaxialflowfans |