Water–Pesticide Integrated Micro-Sprinkler Design and Influence of Key Structural Parameters on Performance

Abstract

The use of pergola trellis crops has led to a need for irrigation and the spraying of pesticides. Thus, a new integrated micro-nozzle was designed to provide water and pesticides. The structural parameters that affect the irrigation performance were selected based on the working principle of the sprinkler. They included the outlet diameter, refractive surface angle, and the distance from the outlet plane to the refractive surface (cone hole distance). The structural parameters that affect the performance of spraying pesticide included the number of diversion chutes, nozzle diameter, and nozzle outer cone angle. The structural optimization of the water–pesticide integrated sprinkler was determined by a single-factor and a three-factors four-levels orthogonal tests. The indices used to evaluate the performance of the sprinkler were irrigation flow rate, wetted radius, and uniformity coefficient. Those used to evaluate the performance at spraying pesticides included the flow rate of spraying pesticides, spray cone angle, and relative size range of the droplets. The entropy weight and the extreme difference analytical methods were used to process the test data. The main order of the influence of key structural parameters on the irrigation performance was obtained as follows: outlet diameter, refractive surface angle, and cone hole distance. The primary and secondary order of the influence on the performance of spraying pesticide was as follows: the number of diversion chutes, angle of the outer cone of the nozzle, and nozzle diameter. The optimal combination of parameters for this water–pesticide integrated micro sprinkler was obtained as follows: outlet diameter 2.0 mm, refractive surface angle 30°, cone hole distance 1.0 d, nozzle diameter 3.0 mm, two diversion chutes, and nozzle outer cone angle 90°. The performance indices included the irrigation water flow rate 0.284 m3/h, wetted radius 4.26 m, uniformity coefficient 91.07%, flow rate of pesticides spread 0.097 m3/h, spray cone angle 121.25°, and average relative distribution span of droplets 1.18. The results provide an important theoretical basis for the practical application of sprinklers.