CFD prototyping of a self-propelled air-assisted greenhouse sprayer adapted for precision horticulture: effect of air speed and deposition assessments in tomato canopies

摘要

Deposition of pesticide droplets on a target can be improved by using optimized sprayer design and adjusting the operating parameters of sprayers. A spraying model based on computational fluid dynamics (CFD) technology was developed and used to evaluate the concepts of a self-propelled air-assisted greenhouse sprayer. The effect of the solid part of the tomato canopy on airflow was modelled by directly introducing an actual three-dimensional architecture of the tomato canopy into the CFD model. The flowers and leaves were represented by the porous regional model. The high-velocity air jet generated by the air-assisted greenhouse sprayer lifts the leaves of greenhouse tomato plants contributing to a significant change in the deposition rate of droplets. Once spray droplets pass through the tomato canopies, the velocity of the air jet is significantly reduced by the resistance of the tomato canopies. The spray droplets deposition also strongly depends on the operating parameter of the sprayer. Both the spray angle and air jet velocity affect the deposition rate on the tomato canopy. The highest deposition rate was attained at the spray angle of 5°. The deposition rate varies with the airflow velocity.