Droplet characterization and water distribution of fixed spray plate sprinkler used in linearly moved irrigation system

Abstract

The irrigation uniformity of sprinkler irrigation system depends on many design factors such as nozzle diameter, operating pressure and riser height. An experimental study was conducted to investigate the effect of combination factors of operating pressure and riser height on water distribution and droplet diameter. To study the droplet characteristics of the fixed spray plate sprinkler (FSPS), droplet diameter and velocity was measured using a Thies Clima laser precipitation monitor. Statistical analysis was conducted on the drop size distribution using volume-weighted method. The volumetric cumulative frequency of drop diameters permitted to reconstruct water application along the sprinkler radius in term of the frequency of drops of different diameters with respect to elevation and working pressure. Wetted diameters and average application rates increased with the increase in pressure and nozzle elevation within a distance of less than 2m from the sprinkler. The results showed that various combinations of the sprinkler could greatly change droplet and water distribution characteristics. Empirical equations for the water distribution from FSPS were also developed with coefficients of determination ranging from 95.0% to 99.6%. The study concluded that the uniformity of a sprinkler irrigation system is more affected by the combination of distance from sprinkler, riser height and operating pressure