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

Abstract In order to determine the spray range of the rotating nozzles, this study conducted a force analysis of the jet micro-element generated by the sprinkler spray, using the dimensional analysis, least squares regression and 207 sets of sprinkler irrigation test data. The jet deformation parameter kjet, which can measure the mass and shape of jet microelements generated by different sprinkler conditions, was proposed. Based on the modified ballistic trajectory equation of the spray water motion, a rotating nozzle spray range model was established, verified and compared, the results showed that: 1) The dimension of jet deformation parameter kjet is the length L, is a function of the nozzle diameter, working pressure and nozzle elevation angle; 2) The maximum mean absolute error (RMSE) and root mean square error (MAE) of this model were1.749 and 1.348, respectively, in the nozzle elevation angle range of 7°~43°, which was significantly better than other types of models in terms of prediction accuracy; 3) Sensitivity analysis yielded the degree of impact on the nozzle range from the largest to the smallest in order of nozzle diameter > nozzle working pressure > nozzle elevation angle > nozzle installation height; 4) The maximum spray range of the nozzle was positively related to the nozzle diameter and working pressure. Influenced by the working pressure and nozzle diameter to reach the maximum spray range of the nozzle elevation angle in the vicinity of 30° change. This study can provide a reference for the design of sprinkler systems and the development of rotating nozzles.