Spray optimization through application and liquid physical property variables–I

Abstract

One of the most important considerations when optimizing a spray application for maximum efficacy and minimum drift is the selection of the optimum droplet size spectrum (Hewitt, A. J., 1997. The importance of droplet size in agricultural spraying. Atomization and Sprays, 7(3), 235–244). Applicators are faced with an extensive selection of nozzle types, tank mixes and adjuvants. The present paper discusses the way that the tank mix and application variables interact to produce specific spray characteristics of droplet size spectrum, coverage and performance in total spray efficiency. Experimental data investigating the effects of liquid physical properties such as dynamic surface tension, shear and extensional viscosity are described. Spray formation from emulsions, surfactants and oils is also discussed. Atomization studies conducted in wind tunnels using a wide range of atomizer and nozzle types under different operating conditions are discussed. Empirical models for predicting atomization and drift of sprays are described with emphasis on their development and practical use for spray optimization.