Droplet Motion Model and Simulation of a Complete Fluidic Sprinkler

Abstract. Simulation and experimental verification of the spray trajectory of a complete fluidic sprinkler was performed. Through further analysis of the forces moving droplets in the air and by exploring the relationship between the air drag coefficient and droplet trajectory, a droplet motion model was established. The velocity of a spray nozzle outlet is a gamma distribution, and the droplet deviation angle is a uniform distribution with a range of 0° to 360° when the sprinkler rotates uniformly for a full circle of spraying. The droplet size distribution in the spray area is approximately log-normal, the wind speed and direction follow a normal distribution, and the initial droplet angle is 27°. Based on a random simulation theory, the droplet trajectories were simulated using MATLAB software. The simulated results show that, compared to the tested value, the error between the simulated and measured values for the average droplet diameter decreased from 53% to 2% with increasing distance. The simulated values for droplet cumulative frequency and droplet speed were nearly the same as the tested value with only a small error. For both droplet distribution and kinetic energy, the relative error was less than 20%. Therefore, the stochastic simulation method can simulate the sprinkler droplet distribution characteristics. Keywords: Complete fluidic sprinkler, Droplet breakup mechanism, Droplet distribution, Droplet motion trajectory.