Design, optimization, and analysis of a new sprinkler with intermittent water-dispersing needle: Integration of RF-NSGA II algorithm and CFD simulation

Sprinklers with fixed water-dispersing needles (FWDN) are widely used in irrigation systems due to their high spray uniformity. However, they have a limited throw radius which increases investment costs. Hence, in this paper, we proposed an innovative sprinkler with Intermittent Water-Dispersing Needle (IWDN) to overcome this limitation. Key parameters of new sprinklers with IWDNs, such as sprinkler rotation speed n, measured in revolutions per minute (rpm); needle insertion frequency f, expressed in insertions per minute (ipm); needle insertion depth h, specified in millimeters (mm); and the distance between the needle and nozzle outlet l, also in millimeters (mm), were investigated. This was done by combining experiments, Random Forest and Non-Dominated Sorting Genetic Algorithm II (RF-NSGA II), and Computational Fluid Dynamics (CFD) simulations. The optimal configuration of the parameters was obtained through analysis, the hydraulic performance was optimized, and finally, the improvement mechanism was analyzed. The results indicated that the RF-NSGA II values matched experimental values, with throw radius errors below 2.82 % and combination uniformity errors under 4.97 %. Optimal matching ranges were n ∈ [0.54, 0.7] rpm, f ∈ [20, 24] ipm, h ∈ [0.43d, 0.48d], and l ∈ [7d, 9.5d], with d = 4.2 mm representing the nozzle outlet diameter. Within the optimal matching range, a set of parameters was selected to configure the IWDN sprinkler, yielding a maximum reduction in combination uniformity of 5.53 % compared to the sprinkler with FWDN. On the other hand, the throw radius increased by at least 29 %. In addition, a jet dispersion rate of approximately 6 % results in a satisfactory combination uniformity. The lower rate of jet velocity decreased and total entropy production in the IWDN accounted for the increased throw radius when the h ≥ 0.3d.