Droplet deposition of agrochemical spraying: comparison of results from a random-walk model and CFD simulations

Abstract

The effectiveness of agricultural spraying processes depends considerably on the ability of the atomized droplets to reach the target site in the desired amount. In this context, mathematical models are suitable tools to predict the deposition of agrochemicals based on process variables. There is still a need to improve the available models to produce more accurate predictions to define appropriate application conditions. The work describes the implementation and comparison of two mathematical models to study the behavior of atomized droplets. A 2D CFD model is used to calculate the trajectories of the droplets and determine their deposition distances, while a lagrangian random-walk (LRW) model is developed to predict the pulverization process of a nozzle. Both models take into account the effects of drag, gravity, buoyancy, and evaporation on individual droplets, as well as the impact of atmospheric stability and dispersion. By tracking a large number of trajectories, meaningful estimates of dispersal statistics can be obtained.