Design and Experimental Testing of a Self-Propelled Overhead Rail Air-Assisted Sprayer for Greenhouse

Greenhouse pesticide application often suffers from low droplet deposition uniformity and health risks to operators. A self-propelled overhead rail air-assisted sprayer has been designed. The mathematical model based on droplet movement and the DPM are used to analyze the equipment’s working principle. Deposition surfaces at 0.4, 0.5, 0.6, and 0.7 m were used to examine the effects of travel speed, external airflow, and spray angle on droplet deposition uniformity. Through one-way analysis of variance, all variables reached a significant level (p < 0.001). Simulation results identified the optimal operating parameters: travel speed of 0.3 m/s, external air-flow velocity of 0.3 m/s, and spray angle of 5°, resulting in droplet deposition densities of 719, 586, 700, and 839 droplets/cm2, with a coefficient of variation of 14.57%. The sediment variation coefficients of both the on-site test results and the simulation results were within 10%, which proved the reliability of the numerical simulation. In conclusion, the device proposed in this study effectively enables targeted fog spraying for multi-layer crops in greenhouses, significantly improving pesticide utilization, reducing application costs, and minimizing environmental pollution. It offers reliable technical support for greenhouse pest control operations.