Effect of Physical Properties of an Emulsion Pesticide on the Atomisation Process and the Spatial Distribution of Droplet Size

Abstract

In the process of applying plant protection sprays, the atomisation process of complex pesticide components such as emulsion pesticides is different from that of water. Indeed, emulsion is often used as an additive to spray to reduce drift. Therefore, this study investigated the different morphological characteristics that occur between emulsions and water during atomisation at different pressures through visualisation experiments and interpreting the formation of structural differences between the two fragmentation mechanisms. The effect of liquid sheet structure on droplet size distribution was analysed in three-dimensional space, not only from one spatial perspective, but how it alters the morphological structures of liquid sheet leading to different potential droplet drift characteristics. It was found that the smaller the liquid sheet disturbance, the more concentrated the droplet size distribution, the more intense the liquid sheet disturbance, the more dispersed the droplet size distribution. The addition of 0.02% emulsion significantly reduced the proportion of V100 (the ratio of volume with drops smaller than 100 μm to the total volume of all droplets) from 21.33% to 10.24%, and the higher the emulsion concentration, the smaller the V100. The ability of the emulsion to increase V400 decreased with increasing pressure.

Anti-Drift Technology Progress of Plant Protection Applied to Orchards: A Review

“…Pesticide adjuvants can change the properties of the liquid, and provide new ideas for reducing spray drift [101]. Some researchers have found that the addition of methylated [102], mineral oil [103], non-ionic adjuvants [104], normaton [105], emulsion [106], and other adjuvants to the liquid can reduce the proportion of minor droplets that are easy to drift, improve the distribution of droplet diameter, and increase the amount of droplet deposition, which has a significant effect on the reduction in pesticide pollution.…”

A Review: Development of Plant Protection Methods and Advances in Pesticide Application Technology in Agro-Forestry Production

“…According to liquid atomization forces, atomization can be divided into capillary tube atomization [131], hydraulic atomization (flat-fan nozzle, swirl nozzle, etc.) [131][132][133], centrifugal atomization with rotating disc (or rotating cage, rotating cup) [131,[134][135][136], aerodynamic atomization (air blast) [131,137], ultrasonic wave atomization [131] and electrostatic atomization [102,103,131], as well as the principle of droplet control and optimal technology [138]. In order to achieve specific spray performance, it is necessary to study nozzles with special requirements and design specific structures with desirable hydrodynamic characteristics, such as low-drift air-induction nozzles [139], variable rate nozzles [140], bypass nozzles to increase flow range [141], rotary cup atomizers for controllable droplets [135], intermittent flow control nozzles using pulse modulation [142], fan-shaped nozzles with a feedback channel to reduce droplet diameter and improve spraying uniformity [143], etc.…”

Study on atomization mechanisms and spray fragmentation characteristics of water and emulsion butachlor

“…The dimensionless number generated by the fluid control equation can be used to describe the relevant physical changes in liquid sheet atomization (Altieri and Cryer, 2018). Within the accuracy range of this experiment, the viscosity has little effect on the droplet size (Kooij et al, 2018), and because of the significant correlation between surface tension and perforation mechanism in multiphase atomization mechanism, this study mainly focuses on the influence of surface tension and inertia force, that is, the Weber number on spray breakup mechanism (Yang et al, 2022). The surface tension of emulsion butachlor and water is measured by the CAM 101 (KSV, Finland) automatic tensiometer using the hanging drop method.…”

“…The atomization process has a significant effect on the droplet size spectrum, and the droplet size has a very important effect on pesticide deposition and anti-drift spray (Yang et al, 2022). When the spray liquid contains oil-based emulsion, it would produce larger droplets than water spray when spraying through a flat fan nozzle, which is of great significance for controlling droplet drift (Hilz et al, 2012;Cryer and Altieri, 2017).…”