Research on the critical impact velocity of droplets impacting metal grid and breaking into sub-droplets

Pesticide drift occurs in the process of pesticide spraying by UAV (Unmanned Aerial Vehicle) and other plant protection machinery. This study proposed a grid atomization method to deal with pesticide drift. First, large droplets that are not easy to drift are sprayed by spray machinery, and then large droplets impact on a metal grid placed above target and break into small droplets suitable for attachment to target, thereby achieving the purpose of reducing pesticide drift and increasing pesticide deposition rate. In order to better realize the breaking of large droplets into small droplets in agriculture, this study researched the influence of different grid materials and grid specifications on critical impacting velocity of large droplets breaking into smaller droplets after impacting it on grid. This study used a high-speed camera to photograph the process of droplets being fragmented into smaller droplets. The size of droplet and impact speed are obtained by image analysis. The experiment results show that there is no obvious difference between the effect of the three materials of stainless steel, nickel and copper on critical impacting velocity under the same grid specifications; Under the experiment conditions, critical impact velocity increases with the increase of mesh number.