Huiyuan Cui, Chengde Wang, Shihui Yu, Zhenbo Xin, Xuemei Liu a b, Jin Yuan

Abstract

In air-assisted spraying, assisted airflow leads to flexible leaf deformation and affects distribution of droplet deposition in canopies. However, analyzing droplet deposition behavior during dynamic changes in canopies is challenging. To address this issue, a method was developed, called two-stage simulation, with one stage involving a fluid–structure interaction of assisted airflow with plant leaves and the other stage involving a discrete particle tracking simulation of droplet deposition within deformed plant canopies under the air–liquid interaction of assisted airflow and droplets. First, a representative three-dimensional (3D) plant model is developed through 3D point cloud scanning, agricultural planting parameters in the field, and plant growth characteristics. Subsequently, the deformed plant model is derived from the results of the fluid–structure interaction simulation. Finally, discrete particle tracking simulations of droplet deposition in canopies of deformed plants under air–liquid interaction are conducted. The accuracy of the simulation is verified by examining airflow distribution in the canopy and the deposition of droplet particles. The airflow verification results indicate accuracy, with a coefficient of determination of 0.8684 and a root mean squared error of 0.1463 for the linear fitted equation between the simulated and measured values. The normalized mean absolute error between the simulated and measured values is 17.2 %, indicating a favorable match between the two. The variance analysis results indicated that there is no significant difference (P > 0.05) between the simulated and measured values of droplet deposition density in the upper, middle, and lower layers. Utilizing the validated computational fluid dynamics (CFD) model, we analyze the deposition characteristics of droplets under varying airflow velocities and spray flow rates. The results highlight a direct correlation between the liquid distribution and generated airflow pattern with increased droplet deposition and drift risk observed under strong airflow and high spray flow rates. This study offers a novel approach to uncovering droplet deposition patterns through CFD simulation.

Paper Linkage:https://doi.org/10.1016/j.compag.2024.109228