Effect of Injection Angle on Drift Potential Reduction in Pesticide Injection Nozzle Spray Applied in Domestic Agricultural Drones

Purpose In this study, the atomization characteristics and drift potential of injection nozzles used in the pesticide injection system of agricultural drones currently used in Korea are evaluated. Furthermore, technical methods to reduce drift potential are determined. Methods To this end, atomization characteristics were evaluated by selecting four representative nozzles commonly used in domestic agricultural drones. Additionally, an experimental device, consisting of a wind tunnel, was constructed to simulate the field situation. Moreover, drift potential was evaluated by using a water-sensitive paper under side wind conditions. Results The VMD and RSF of the nozzles used in the test were shown high in the order of TX–XR–TP, and the number density was low in in the order of TX–TP–XR. Thus, the evaluation of the droplet drift potential with respect to the side wind revealed that large amount of droplet drift occurs due to the side wind of 1 m/s, and the droplet drift of all nozzles used in the experiment, with the exception of the AI nozzle, was high. When the nozzle was installed obliquely, considering the flight speed and flight angle of the drone, it was confirmed that the tilt angle of the nozzle installation affects drift reduction. This applies even to nozzles that produce small droplets of less than 200 μm. Furthermore, as the speed of the side wind decreases, the drift reduction effect increases. Conclusion Given that the drift potential of XR and TP nozzles, which are currently most commonly used in agricultural drones, are evaluated to be weak, auxiliary drift reduction methods, such as nozzle tilt angle, should be actively considered to reduce drift potential and minimize environmental damage.