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| DOI：10.13522/j.cnki.ggps.2021143 |
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| Distribution of Water Droplets of Non-circular Sprinkler Nozzles |
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LIU Jialing, WAN Jixiang, LI Hao, et al
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| Abstract: |
| 【Objective】The distribution of water droplet diameter of the sprinkler nozzle is an important parameter in designing sprinkler irrigation. The purpose of this paper is to study how non-circular nozzles affect this distribution.【Method】We studied two non-circular nozzles: an rhombic nozzle and an elliptical nozzle. By keeping the spraying rate the same, we compared the distribution of water droplet diameters of each nozzle using the PY15 rocker arm by keeping the working water pressures in the range of 100 to 300 kPa. For each test, we measured the distribution of the droplet diameters using a video raindrop spectrometer, with that measured from round circular nozzle taken as the control.【Result】The diameter of coverage of all nozzles was ranked in the order of round > rhombic > elliptical. Shape coefficient of the non-circular nozzle decreased as the outlet diameter of the nozzle increased while increased as the length-diameter ratio increased. The diameters of water droplets of the rhombus nozzle increased most quickly in the radial direction, compared to the other two nozzles. When working water pressure was the same, the diameter of the end-water droplet decreased as the shape coefficient of the nozzle increased; the diameter of the coverage increased with the diameter of the nozzle outlet. Increasing the outlet diameter can speed up the droplet velocity, while increasing the diameter-length ratio reduces the maximum distance that the droplets can reach due to the increased droplet diameter and velocity. The increase in droplet velocity of the elliptical nozzle with droplet diameters was the least. The kinetic energy and the increase in amplitude of unit volume of the droplets at the same location both decreased as the working water pressure increased. The diameter and kinetic energy of the droplets increased with the radial distance exponentially and linearly, respectively, while the relationship between velocity and diameter of the droplets was logarithmic.【Conclusion】Geometrical shape of the sprinkler nozzle has a significant impact on the diameters of the water droplets and their spatial distributions. |
| Key words: Non-circular nozzle; water droplet diameter; kinetic energy; spatial distribution |
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