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Theoretical modelling, design and testing of a novel low pressure spray sprinkler for travelling agricultural irrigation systems.

Budler, Michael John Ian (2017-12)

Thesis (MEng)--Stellenbosch University, 2017.

Thesis

ENGLISH ABSTRACT: A novel, overhead spray sprinkler concept is developed for travelling irrigation systems including centre pivot and linear-move systems. The Powasave sprinkler is a low pressure spray sprinkler with the potential to reduce operating pressures in travelling irrigation systems by up to 35%, and produce a uniform spray droplet size. The core components of the Powasave sprinkler, and their functions, were discussed in this study and a theoretical model developed to simulate the spray characteristics beneath the sprinkler. The model was used to design a sprinkler prototype that was manufactured and installed on a centre pivot system in the Western Cape. The application uniformity of the Powasave sprinkler prototype was evaluated in a series of distribution tests conducted beneath the centre pivot system. The distribution uniformity (DU) and coefficient of uniformity (CU) beneath the sprinkler prototype was evaluated and compared against two commercial spray sprinklers also installed on the centre pivot system: the Nelson D3000 Sprayhead sprinkler, and the S3000 Spinner sprinkler. A comparison of the results show the Powasave sprinkler having a poor uniformity relative to the Sprayhead and Spinner sprinklers. Where the CU beneath the Powasave sprinkler was measured to be 64%, the CU measured beneath the Sprayhead and Spinner sprinklers were 77% and 94% respectively. Adjustments to the Powasave sprinkler design were recommended to improve the application uniformity to be more competitive with that of the Nelson sprinklers. Although the Powasave sprinkler concept has the potential to reduce operating pressure in travelling irrigation systems, it does not yet have the application uniformity attainable by the commercial spray sprinklers used in the industry.

AFRIKAANSE OPSOMMING: ‘n Nuwe oorhoofse spuitbesproeier konsep word tans ontwikkel vir bewegende besproeiingstelsels, insluitende spilpunt- en lineêr-bewegende stelsels. Die Powasave besproeier is ‘n laedruk spuitbesproeier wat die potensiaal het om operasionele druk in bewegende besproeiingstelsels tot en met 35% te verlaag, asook om ‘n eenvormige sproei druppelgrootte te skep. Die kern komponente van die Powasave besproeier en hul funksies word in hierdie studie bespreek. ‘n Teoretiese model is ontwikkel om die eienskappe van die sproeiwater onder die besproeier te simuleer. Hierdie model is gebruik om ‘n prototipe te ontwerp vir ‘n besproeier wat vervaardig en geïnstalleer is op ‘n spilpuntstelsel in die Wes-Kaap. Die toedieningseenvormigheid van die Powasave besproeier prototipe is geëvalueer met behulp van ‘n reeks verspreidingstoetse wat onder die spilpuntstelsel uitgevoer is. Die toedieningseenvormigheid en koëffisiënt van eenvormigheid onder die besproeier prototipe is geëvalueer en vergelyk met twee kommersieel beskikbare besproeiers wat ook op die spilpuntstelsel geïnstalleer is: die Nelson D3000 Sprayhead besproeier en die S3000 Spinner besproeier. ‘n Vergelyking van die resultate toon dat die Powasave besproeier oor swak eenvormigheid beskik in verhouding tot die Sprayhead en Spinner besproeiers. Die koëffisiënt van eenvormigheid, gemeet onder die Powasave besproeier, was 64%, waarteenoor die koëffisiënt van eenvormigheid, soos gemeet onder die Sprayhead en Spinner besproeiers, onderskeidelik 77% en 94% was. Die aanbeveling is derhalwe dat die ontwerp van die Powasave besproeier aangepas word om die toedieningseenvormigheid te verbeter en sodoende meer kompeterend te wees met die Nelson besproeiers. Alhoewel die Powasave besproeier konsep die potensiaal het om operasionele druk te verlaag in bewegende besproeiingstelsels, beskik dit nog nie oor die toedieningseenvormigheid wat bereik kan word deur die kommersiële besproeiers in die bedryf nie.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/102916
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