A Study on the Drift of Spray Droplets Dipped in Airflows with Different Directions

Abstract

The European Directive concerning pesticide sustainable use establishes regulations to reduce the environmental drift throughout treatments to agricultural crops, particularly in nearby sensitive areas, such as water bodies, natural reserves and urban areas. The drift represents the fraction of mixture delivered by the sprayer that is not caught by the crop, and is the clearest cause of environmental pollution. Anti-drift nozzles are usually employed, and buffer zones are also maintained along the edges of the sprayed field to reduce drift production. The aim of this work was the theoretical study of the motion of the spray droplets delivered by a nozzle, dipped in downwards and/or lateral forced air flows. A mathematical model has been developed, consisting of a system of 2nd order differential equations, to simulate the motion of water droplets of different diameters within simultaneous different directions of air flow. The graphs, obtained by means of the numerical solution of the model, allow us to analyze the level of the droplets’ drift, according to their diameter and to the speed of the lateral and the downward air flows, respectively. A lateral airflow at a speed of 5 m · s − 1 produced a drift in its direction until 1.70 m for droplets from 100 to 500 μm in diameter. For larger drops, the impact of the downward airflow is not very significant. The results obtained by the numerical solution of the mathematical model have been compared with the results of experimental tests carried out to evaluate the drift of spray produced by different nozzles.

Insights on droplet drift and effective utilization of pesticide in “Third Pole”：Qinghai-Tibet Plateau of China

“…The majority of the study has been focused on starting diameter dispersion and ultimate effectiveness of deposition plants, both experimentally and numerically [ [20] , [21] , [22] ]. However, droplet distortion, collision, and evaporation between the nozzle and the target are absent.…”

Spraying performance of umbrella wind‐field‐type atomization and its application to parameter optimization

“…The effects of application parameters and airflow velocity on droplet deposit and the spray drift rate were also investigated, and multiple regression models were used to predict the droplet deposit and drift rate. Guiju et al 15 . designed a V‐shaped spraying device to investigate the effect of a V‐shaped wind field on droplet deposit in the canopy and to reduce spray drift between fruit tree rows.…”

“…14 The effects of application parameters and airflow velocity on droplet deposit and the spray drift rate were also investigated, and multiple regression models were used to predict the droplet deposit and drift rate. Guiju et al 15 designed a V-shaped spraying device to investigate the effect of a V-shaped wind field on droplet deposit in the canopy and to reduce spray drift between fruit tree rows. Moreover, Changxi et al 16 designed a conical wind-field-type anti-drift spraying device to clarify the conical wind field's effect on the droplet deposit effect through spraying tests; reduce the ambient airflow velocity's effect on droplet movement using a conical wind field; reduce spray drift; analyze the anti-drift device's anti-drift principle; improve the anti-drift spraying effect; and optimize the device design.…”

Synchronous three-dimensional detection method for multiple parameters of wind fields based on vector principle

“…With the help of strong wind fields, droplets are delivered onto targets. At present, droplet deposition in crop canopies is not ideal during spraying, characterizing the issues of uneven distribution, inadequate penetration and significant drift ( Pascuzzi et al, 2020 ; Zheng et al, 2020 ; Zhang et al, 2020 ). The fundamental reason is that the attenuation law of the wind field influenced by canopies has not been clearly studied, whose core difficulty is lacking effective detection approaches for the speed and flow direction of the wind in canopies.…”