Measurement of drop spectra from rotary cage aerial atomizers

Abstract The drop spectra produced by various examples of Micronair AU3000 rotary cage atomizer were measured using a laser-based Particle Measuring Systems optical array probe. To simulate aerial application by fixed-wing aircraft, the atomizers were mounted in an open jet wind tunnel operating in the range 130–225 km h−1. An empirical model which predicted the volume median diameters (VMDs) and volume quartiles of the spectra was developed. The model showed a high degree of correlation with the experimental results. The model took into account not only the speed of rotation of the cage, but its diameter, the liquid flow rate, and the air speed of the aircraft. The model showed general agreement with research into rotary disc atomization. Although a water-based liquid was used in the tests, it was concluded that the model would be suitable for use as a performance guide for most pesticide formulations.