Modelling the spray range of rotating nozzles based on modified ballistic trajectory equation parameters

Abstract

AbstractThe nozzle spray range is an important parameter in the design of sprinkler systems because it affects the wetted area and water application rate. In this study, the jet deformation parameter kjet, which can measure the mass and shape of the jet microelement, was investigated, and a spray range prediction model for a rotating nozzle was established based on the modified ballistic trajectory equation. A comparison verified the accuracy of the model, and the degree of influence of different factors on the spray range was analysed. The results showed the following: (1) The dimension of the jet deformation parameter kjet is the length L, which is a function of the nozzle diameter, working pressure and nozzle elevation angle. (2) The maximum mean absolute error and root mean square error of the current model at a nozzle elevation angle of 24° were 2.038 and 1.603, respectively, representing a maximum increase in prediction accuracy of 87% and 86.7%, respectively, over other models at the same angle. (3) A sensitivity analysis revealed that the factor with the greatest impact on the nozzle spray range was the nozzle diameter, and the smallest was the nozzle mounting height. (4) The maximum nozzle spray range was positively related to the nozzle diameter and working pressure, and the nozzle elevation angle varied at approximately 30° when the maximum range was reached. This study provides a reference for the design of sprinkler systems and the development of rotating nozzles.