Structure optimization and droplet deposition characteristics of centrifugal atomizing nozzles

Aiming to address the issue of uneven nebulization and poor targeting of liquid pesticide caused by the mismatch between the aerial spraying equipment and operating parameters of the current plant protection UAV, the droplet deposition characteristics of the turntable centrifugal atomizing nozzle were optimized. The effects of spray flow and rotation speed of the atomizing disc on the diameter, uniformity and coverage of centrifugally atomized droplets were explored by establishing a variable spray platform. The centrifugal atomizing discs with different structures were constructed by 3D printing technology, and the relative influence of diameter, teeth, and cone angle on droplet deposition characteristics was analyzed by orthogonal tests. The analysis of variance results show that under the same flow rate, the rotation speed of the atomizing disc is negatively correlated with the volume median diameter and relative span of the droplet spectrum. Increasing the rotational speed expands the effective spray area. The spray flow is positively correlated with the droplets coverage rate and volume median diameter, but excessive flow will lead to uneven droplet deposition. The influence of the diameter of the square atomizing disc on the droplet size is statistically significant. With the increase of the diameter, the droplet volume diameter gradually decreases. By estimating the mean boundary value, the optimized atomizing disc diameter is 65 cm, the number of teeth is 180, and the cone angle is 30°. Based on the above optimized results, a UAV spraying experiment in a tea garden is carried out to verify the feasibi-lity of the improved nozzle.