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

[摘要] ENGLISH ABSTRACT: A novel, overhead spray sprinkler concept is developed for travelling irrigationsystems including centre pivot and linear-move systems. The Powasave sprinkler is a low pressure spray sprinkler with the potential to reduce operating pressuresin 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 sprinklerprototype 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. Thedistribution uniformity (DU) and coefficient of uniformity (CU) beneath the sprinkler prototype was evaluated and compared against two commercial spray sprinklersalso 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 uniformityrelative to the Sprayhead and Spinner sprinklers. Where the CU beneath thePowasave sprinkler was measured to be 64%, the CU measured beneath the Sprayhead and Spinner sprinklers were 77% and 94% respectively. Adjustmentsto the Powasave sprinkler design were recommended to improve the application uniformity to be more competitive with that of the Nelson sprinklers. Although thePowasave 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.

[发布机构] Stellenbosch University