Experimental Study on Spray Characteristics of Centrifugal Nozzle for Plant Protection UAV under Wind Tunnel Condition

In order to research on spray characteristics of the P20 centrifugal nozzle, the nozzle was tested in this article. Through single factor experiment method, firstly, the influence of flow rate, rotational speed and spraying height on spraying amplitude was measured. Secondly, under different wind speeds, the influence of flow rates, rotational speed, vertical height of nozzle to laser and horizontal distance of nozzle to laser on droplet size was measured. Finally, the distribution of droplet deposition in nozzles was measured by combining with water sensitive paper at different wind speeds. The results showed that the increase of the flow rate caused the spray amplitude to increase, the increase of the rotational speed caused the spray amplitude to fluctuate within a range and the increase of the height caused the spray amplitude to decrease. In the absence of wind, the flow rate and height increase had no significant effect on the size of the droplet size, the increase of the rotational speed caused the droplet size to decrease and the increase of the horizontal distance between the nozzle and the laser caused the overall value of the droplet size to increase. Under the condition of wind, the increase of wind speed caused the droplet size to decrease slightly. The amount of droplet deposition also decreased as the wind speed increased in the same region. This experiment provided data support for parameter values of nozzle during UAV spray and was convenient for further optimization of nozzle.