Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The performance of wet cooling towers can be improved by installing spray
nozzles that distribute the cooling water uniformly onto the fill whilst operating at
a low pressure head. In this thesis, three commercial spray nozzles are
experimentally evaluated in terms of flow and pressure loss characteristics as well
as water distribution patterns. The results of the evaluation process highlight the
need for spray nozzles with enhanced performance characteristics. The theory
required to implement the results of the evaluation process in the design of a
cooling tower is presented and discussed. A systematic approach to enhance the
performance of a spray nozzle through minor alterations is applied to one of the
commercial spray nozzles that was evaluated. The fluid dynamics of an orifice
nozzle, such as the effect of a change in pressure head, spray angle, spray height,
orifice diameter and wall thickness on drop diameter and spray distance, is
experimentally investigated and a model with which a spray nozzle can be
designed is finally presented. Two prototype spray nozzles show that it is possible
to enhance the performance of spray nozzles and thus wet cooling towers by
means of the methods presented. / AFRIKAANSE OPSOMMING: Die werkverrigting van natkoeltorings kan verbeter word deur sproeiers te
installeer wat die verkoelingswater uniform versprei op die pakking teen 'n lae
pomp drukhoogte. In hierdie tesis word drie kommersiële sproeiers
eksperimenteel geëvalueer in terme van vloei en drukverlies eienskappe sowel as
water verdelings patrone. Die resultate van die evaluasie proses beklemtoon die
behoefte aan sproeiers met verbeterde werkverrigtingseienskappe. Die teorie wat
benodig word om die resultate van die evaluasie proses te implementeer in die
ontwerp van 'n natkoeltoring word bespreek. 'n Stelselmatige benadering om die
werkverrigtings van 'n sproeier te verhoog deur klein veranderinge aan die
ontwerp aan te bring, word toegepas op een van die sproeiers wat getoets is. Die
vloeidinamika van 'n plaatmondstuk, soos die effek van 'n verandering in
drukhoogte, sproeihoek, sproeihoogte, gatdiameter en wanddikte op druppel
diameter en sproeiafstand, is eksperimenteel ondersoek en 'n model word
aangebied waarmee 'n sproeier ontwerp kan word. Twee prototipe sproeiers wys
dat dit moontlik is om die werkverrigting van sproeiers, en dus ook
natkoeltorings, te verbeter deur die metodes wat in die tesis aangebied word, toe
te pas.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/71944 |
| Date | 12 1900 |
| Creators | Roux, Daniel |
| Contributors | Reuter, H. C. R., 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 |
| Rights | Stellenbosch University |
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