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

Due to the complex structure of the pressure-adjusting device used in most sprinklers for variable irrigation, it is not possible to observe the flow behavior of the water passing through the flow field. In this paper, an integral three dimensional (۳D) numerical model based on the structural characteristics of the fluidic sprinkler was constructed to simulate the flow field distribution using computational fluid dynamics (CFD). A new type of fluid sprinkler (BPXH) was used in the experiments. The main stream region and the variable velocity regions were clearly distinguished, and the details of the variations in pressure are discussed. The results indicated that the simulation methodology generated sufficient data to analyze the sprinkler pressure and outlet velocity changes. The minimum error of the difference between the simulation and the test pressure values was ۰.۰۴۹, with a maximum of ۰.۱۴. The turbulence model could accurately predict the relationship between the outlet velocity and the wetted radius. The outlet velocity ranged from ۱۲.۶ to ۱۷.۹ m s-۱ during the simulation under the variable inlet boundary conditions of the sprinkler. Both the simulation and test values of the wetted radius increased gradually with the sprinkler rotating angle. The absolute error of the simulation and the test ranged from ۰.۰۷ to ۰.۱۶. Computational fluid dynamics provides a promising tool to help in the design of pressure-adjusting devices using a new type of variable-rate fluidic sprinkler.