Droplet Size Distributions from Different Shaped Sprinkler Nozzles

Abstract

Sprinklers with circular and noncircular nozzles were tested to determine their droplet size distributions and water application patterns. Circular nozzles usually produced greater wetted radii and larger droplet diameters than noncircular nozzles, however, noncircular nozzles gave higher overlapped uniformity coefficients. Droplet formations from noncircular nozzles were compared with those from circular nozzles and it was found that noncircular nozzles created greater portion of droplets with diameter less than three millimeters at a given pressure. It is therefore confirmed that noncircular nozzles have the advantages of providing an acceptable water application pattern and a smaller portion of larger droplets over the entire precipitation profile at low operating pressure. A simple exponential model was developed to represent droplet size distributions from both circular and noncircular nozzles. The exponential model gave results similar to an upper limit lognormal (ULLN) model.