Droplet impingement behavior analysis on the leaf surface of Shu-ChaZao under different pesticide formulations

Abstract

Spray deposition in agriculture is of particular importance to apply pesticides to plant because poor efficiency leads to reduced biological efficacy, environmental contamination and even economic losses. Spray deposition on leave surfaces is associated with impingement dynamics behaviors of pesticide droplets. But how this impact affects the foregoing deposition is an intriguing subject of research, notably for the deposition on tea leave-surfaces. In this study a tea leaf-surface of a real tea tree, i.e. Shu-Chazao was selected as an impingement target of the pesticide droplet. A Couple Level Set & Volume of Fluids (CLSVOF) interface tracking method was proposed to characterize the impingement dynamics behaviors of the three commonly used pesticide droplets (such as chlorothalonil, dimethoate and malathion) on the leaf-surface and thus assess the effects of the different pesticide formulations on the spray deposition. Four key factors, including liquid phase pattern, surface wettability, pressure and velocity distributions were investigated, respectively, along the transverse and longitudinal directions of the leaf-surface. The calculated predictions provide a reasonable match with the published data. With our study, the CLSVOF interface trace modeling is demonstrated to have great potential for in-depth study of the impingement dynamics behaviors of the pesticide droplets on the tea leaf-surface. The simulation results can contribute to spray efficiency improvement of the tea plants in China.