Numerical Simulation and Experimental Study on a New Type of Variable-rate Fluidic Sprinkler

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Due to the complex structure of the pressure-adjusting device used in most sprinklersfor variable irrigation, it is not possible to observe the flow behavior of the water passingthrough the flow field. In this paper, an integral three dimensional (3D) numerical modelbased on the structural characteristics of the fluidic sprinkler was constructed to simulatethe flow field distribution using computational fluid dynamics (CFD). A new type of fluidsprinkler (BPXH) was used in the experiments. The main stream region and the variablevelocity regions were clearly distinguished, and the details of the variations in pressureare discussed. The results indicated that the simulation methodology generated sufficientdata to analyze the sprinkler pressure and outlet velocity changes. The minimum error ofthe difference between the simulation and the test pressure values was 0.049, with amaximum of 0.14. The turbulence model could accurately predict the relationshipbetween the outlet velocity and the wetted radius. The outlet velocity ranged from 12.6 to17.9 m s-1 during the simulation under the variable inlet boundary conditions of thesprinkler. Both the simulation and test values of the wetted radius increased graduallywith the sprinkler rotating angle. The absolute error of the simulation and the test rangedfrom 0.07 to 0.16. Computational fluid dynamics provides a promising tool to help in thedesign of pressure-adjusting devices using a new type of variable-rate fluidic sprinkler.