Journal of Taiwan Agricultural Research

Author:Jyh-Rong Tsay, Lien-Sheng Liang and Lung-Hu Lu

Abstract:

    Air-assisted spraying has been among the strategies recommended for reducing spray drift. Even though many studies pertaining to air-assisted spraying had shown its advantages on reducing spray drift, little information about optimal operating parameters and the effect of wind velocity, sprayer travel speed, and sprayer travel direction on reducing spray drift for air-assisted spraying was available. In this study, the evaluation of air-assisted spraying system based on comparing effects on drift reduction was conducted by using a computational fluid dynamics software FLUENT® and a response surface method. The relative drift indexes of air-assisted spraying under various wind velocities, sprayer travel speeds, and sprayer travel directions were also investigated. Main conclusions drawn from this study were stated as follows. The angle between the air jet and nozzle of air-assisted spraying has no significant influence on reducing spray drift. With relative drift indexes from -50% to -80%, the air current with velocities from 20 to 30 m/s, commonly used by air-assisted spraying, seems to be acceptable in reducing spray drift for downwind spraying. However, with relative drift indexes from -5% to -22%, the air current with velocities from 20 to 30 m/s of air-assisted spraying needs to be increased properly to improve the ability of drift reduction. Variations of relative drift indexes of air-assisted spraying under various wind velocities, sprayer travel speeds, and sprayer travel directions could be explained by local relative wind velocity. The higher the local relative wind velocity, the greater the relative drift index. Results of this study provide the practical operations of air-assisted spraying with useful information, which is beneficial for reducing spray drift from air-assisted sprayers.

Key words:Air-assisted spraying, Evaluation, Simulation

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