Atomization characteristics of multi-nozzle electrostatic spray and field experiment

Abstract: Aiming at the problems such as large water demand, insufficient deposition of droplets on the leaf back of the traditional sprayer, and uneven distribution of droplets, etc, a spraying technology combining electrostatic spray with spray rod spray was proposed in this paper. Based on the theory of electrostatic field and the principle of inductive charge, the mathematical model of the induced electric field strength was established, and theoretical calculations were performed for the electric field strength of different numbers of induction electrodes. In order to explore the best working parameters of the electrostatic sprayer and clarify the influence of different parameters on the atomization effects of droplets, the simulation model was established by using Fluent software. The simulation model included spray flow field, droplet dispersion field and electric field. By setting different boundary conditions and control equations, the spray flow field, droplet dispersion field and electric field were coupled to calculate. The simulation results showed that the uniformity of electric field distribution in spatial of multi-nozzles was better than that of single nozzle, and the droplet volume diameter of electrostatic spray decreased by 12.7% compared with non electrostatic spray. The electrostatic spray test platform was built, taking the spray water pressure, charging voltage and nozzle spacing as experimental factors, the charge-mass ratio, droplet diameter, uniformity of droplet distribution and deposition of droplets as experimental indexes, the deposition characteristics of droplets were tested The results showed that the maximum charge-mass ratio of droplets of multi-nozzle was 0.26 mC/kg, which was 52.9% higher than that of single nozzle. Compared with non electrostatic spray, the uniformity variation coefficient of droplet distribution was reduced by 32.1%, the volume diameter was reduced by 14.8%, the droplet adhesion rate on the leaf front in the upper, middle and lower sampling layers increased by 27.1%, 37.3% and 45.2% respectively for the electrostatic spray, and the droplet adhesion rate on the leaf back increased to 26, 17 and 12 in unit cm2 respectively, the deposition quality decreased by 25.7%, 25.0% and 12.5% respectively. The best operation parameters combination of electrostatic spray determined by experiments was that the charging voltage was 6 kV, the spray water pressure was 0.4 MPa, and the distance between the adjacent nozzles was 250 mm. The field experimental results showed that the control effect of the electrostatic spray and conventional spray were 92.1% and 95.0% respectively, the control effects were basically the same. The water demand of electrostatic spray decreased by 60%, and the working area at full capacity increased by 1.5 times.The study provides a reference for the application of electrostatic spray technology on large boom sprayer.