Abstract
Application of agrochemicals on crops is important for plants protection. Multiple factors influence the application of
agrochemicals on plants such as climatic conditions, crop characteristics and spraying system design. There is a need for
reliable methods to investigate these properties more precisely with low cost and in reasonable time. In the present study, the
velocity distribution of an extended flat fan nozzle is investigated to determine the weak jet areas, which have high risks of
droplet drift. Two methods are used and compared: the Particle Image Velocimetry (PIV) method used as an experimental
approach versus a Computational Fluid Dynamics (CFD) with volume of fluid (VOF) integrating k-epsilon model as a
simulation approach. The nozzle was operated at eight different pressures on a custom-made nozzle operating prototype while
ANSYS 16 Fluent software was employed for the simulation approach. The obtained findings showed three significant results.
First, the spray sheet (jet) has maximum velocity in its center. Second, the particles present in the central region of spray sheet
have maximum kinetic energy and this region has the ability to hit the right target on the plant surface, while liquid particles
present in the surroundings of this central area have less velocity with minimum kinetic energy and have maximum chances to
be off-target during spraying. These particles can move away from the targeted surfaces easily even with very low wind
velocity. Third, the study also showed that PIV and CFD simulation methods were in agreement and both showed reliable
ways to measure the jet velocity and plot the velocity distribution under the sprayer nozzle. The applications of these findings
are also discussed.
