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Comprehensively evaluating and modelling droplet diameters and kinetic energies of low‐pressure sprinklers

Proper droplet diameter and kinetic energy can effectively reduce the risk of soil erosion during low‐pressure sprinkler irrigation. In this study, we comprehensively evaluated the radial distributions of droplet diameter, velocity, kinetic energy, kinetic energy per unit droplet volume, and specific power for three common low‐pressure sprinklers, i.e. Nelson D3000, R3000 and Komet KPT, with two operating pressures (103 and 138 kPa) and three nozzle outlet diameters (3.97, 5.95 and 7.94 mm). Additionally, the relationships between these droplet characteristic parameters were analysed. Overall, the maximum values of five characteristic parameters were observed at the end of the jet under various treatments. Although R3000 had a larger droplet diameter (0.10–6.42 mm) and kinetic energy (1.08 × 10−10–8.59 × 10−3 J) distribution range than D3000 and KPT, the D3000 specific power (mean value of 0.4274 W m−2) was the highest of the three sprinklers. Therefore, KPT was suggested more in low‐pressure sprinkler irrigation than in the other two sprinklers because its application rates were reduced along the radial direction. In addition to selecting a suitable sprinkler type for minimizing specific power, determining a reasonable sprinkler spacing was also significant (P < 0.01). Furthermore, a universal specific power model with an appropriate accuracy (RMSE = 0.011 W m−2, NRMSE = 29%) was proposed. This study provides a key basis for the selection and combination of low‐pressure sprinklers.