Theoretical and Experimental Study on Water Offset Flow in Fluidic Component of Fluidic Sprinklers

Abstract

Compared with other rotating sprinklers, the fluidic sprinkler controlled by an outlet clearance has a simpler structure and better hydraulic performance. The offset effect, happening in the fluidic component of the sprinkler, drives the sprinkler and controls its rotational direction. Theoretical and experimental research are conducted to study the water offset jets with a small ratio of 0.675 for the 10PXH sprinkler and 0.355 for the 30PXH sprinkler in the fluidic components. Analytic solutions and other calculations deduce the reattachment lengths of the offset jets. Computational fluid dynamics (CFD) software simulates the offset flows in simplified models and real models of the fluidic components, in two dimensions and three dimensions, respectively, utilizing the volume of fluid (VOF) method to trace the shape of the interface between water and gas. Simulation results of the sidewall pressure distribution also obtain the reattachment lengths. The resulting experimental measurements of the static pressure and reattachment length are in line with the predicted results of the calculations and the simulations. These results indicate that CFD simulation can approximate the offset flow in fluidic components. On the basis of this study, some of the component sizes are confirmed.