Structural parameter design for variable regulatorsinprecision irrigation sprinklers
(1.College of Mechanical and Electronic Engineering, Northwest A＆F University, Yangling, Shaanxi 712100, China; 2.Institute of Soil and Water Conservation, CAS＆MWR, Yangling, Shaanxi 712100, China)
Abstract：In order to simultaneously control the spray field and volume of sprinklers in accordance with various shapes of irrigation area, a variable regulator design for precision irrigation sprinklers is proposed. The variable regulator was constructed with upper and lower waterblocking pieces, each of which comprises a central throughhole as well as fanshaped throughholes and fanshaped waterblocking pieces. As the sprinkler rotates, the upper and lower waterblocking pieces rotate in opposite directions. In conducting, both the watercarrying area and spray range increase; when it is closed, both the watercarrying area and spray range decrease. In this study, the structural parameters, including the central angle of the fanshaped and central throughholes for minimizing the sprinkler energy loss, were designed; based on the local resistance theory of water movement, the central throughhole diameters for the upper and lower waterblocking pieces were also designed. The results show that the variable regulator designed in this study can guarantee the minimal resistance loss at watercarrying cross section; through spray range and watercarrying area testing, it is found that the contours of sprayed areas has transformed from circles to approximately squares, with the largest range approaching closely the original nozzle range and the water distribution being even, which can meet the demand of controlling spray flow and spray range as they vary and realize variablerate precision irrigation.
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