The Effect of Fluid Properties on the Spray Quality from a Flat Fan Nozzle

摘要

The quality of sprays from a flat fan nozzle (8002) is demonstrated for water-based fluids of three types: surfactant solutions, dispersions and polymer solutions. The characteristics of these sprays are contrasted with the very different behavior of sprays formed from emulsions. The effects of concentration and oil droplet size of emulsions on the spray droplet size distribution and spray pattern are presented and discussed. Separate measurements of the spray angle, sheet breakup length, droplet size distribution and spray pattern along the fan width and thickness, using photography and a patternation method, are reported. These data and images from high speed photography of the break-up region of the spray show that emulsions cause premature disruption of the spray sheet, shifting the distribution of droplet sizes to larger values. Data from sprays of various emulsions support the hypothesis that disruption is the result of the presence of hydrophobic regions formed by the rapid stretching of the surface of the hydrophobic liquid droplets. Some advantages of emulsions over water-soluble polymers for spray drift control are presented.