Droplet characterisation of a complete fluidic sprinkler with different nozzle dimensions

• Droplet characterisation of CFS studied via droplet diameter model.
• Lognormal distribution used to evaluate drop diameter distribution with distance.
• Cumulative volume distribution followed Boltzmann function distribution.
• Droplet kinetic energy for the three nozzles used in CFS was obtained.

The complete fluidic sprinkler (CFS) has the advantages of a simple structure and the ability to work well at a lower nozzle pressures. CFS is a gas–liquid fluidic sprinkler, whose driving moment is achieved by a flow reaction as a result its droplet characteristics differ from those of conventional sprinklers. To study the droplet characteristics of the CFS, droplet diameter and velocity were measured using a Thies Clima laser precipitation monitor (TCLPM). Statistical analysis was conducted on the droplet size distribution using a volume-weighted method and droplet velocity was analysed using a number-weighted method. The results showed that volume mean droplet diameter and volume medium diameter increased with the distance from the nozzle and decreased with the nozzle size. The frequency of droplets with a diameter <3 mm increased with the working pressure. The number of larger droplets decreased with pressure and increased with the nozzle size when the pressure was 0.25, 0.30, or 0.35 MPa. A lognormal distribution model was used to evaluate the drop diameter distribution for each observed distance. With increasing pressure, the slope of the cumulative volume frequency droplet size curve at different distances from the nozzle decreased, and the distribution followed the trend of a Boltzmann function distribution. Droplet velocity increased with the droplet diameter but was not significantly influenced by the nozzle pressure. The results may provide a basis for further systematic research on the CFS.