静电喷嘴雾化特性与沉积效果试验分析

Analysis and Experiment on Atomization Characteristics and Spray Deposition of Electrostatic Nozzle

为了探究电极材料对静电喷嘴雾化效果和荷电性能的影响,确定设计的静电喷嘴的最佳作业参数,并明确静电作用对雾滴沉积效果的影响,以电极材料、电极电压、喷施压力和喷孔直径为喷施变量,针对设计的静电喷嘴进行室内雾化和沉积试验。研究结果表明:设计的静电喷嘴最佳电极电压为8 k V,最佳电极材料为紫铜,最佳喷施压力为170 k Pa;相比于非静电喷雾,静电作用开启后,静电喷嘴的有效喷幅增加约50 cm;在3个采样层的雾滴沉积密度依次增加了23、19、10个/cm2;在喷嘴雾化的所有雾滴中,粒径在50~120μm区间的雾滴受静电作用影响最大,静电作用开启后,此区间段内的雾滴沉积数量增加了约2倍,当雾滴粒径大于120μm时,雾滴沉积密度随雾滴粒径的增大呈下降趋势;沉积的雾滴主要是粒径在180μm以下的雾滴,因此适合最佳生物粒径为180μm及180μm以下的作物。

Electrostatic charging of sprayed pesticide was realized in electrostatic spray nozzle design, which improved plant coverage and reduced wasted pesticide as well as soil pollution. The performance of electrostatic spray nozzles depended on the charge to mass rate of droplets. The preface illustrated six factors that can impact on the efficiency of the induction nozzle and the electrostatic spraying agricultural application, including nozzle geometry, nozzle air pressure, nozzle flow rate, applied voltage, electrode geometry, electrode position and materials, the properties of the sprayed liquid used and environment factors around the spray. In order to study the effect of electrode material on atomization characteristics and charge performance of electrostatic nozzle, optimize the spray parameters and explore the influence of electrostatic force on spray deposition, four experimental variables were designed, including the electrode material, electrode voltage, spray pressure and hole diameter of electrostatic nozzle, and the indoor atomization and deposition test were carried out. The results showed that the optimal electrode voltage was 8 kV, the optimal electrode material was copper and the optimal spray pressure was 1.7 × 10^5 Pa. Compared with non-electrostatic spraying, the spray swath width of electrostatic nozzle was increased by 50 cm. Of all droplets, the electrostatic force had the most effect on the droplets （between 50 μm and 120 μm） , making the deposition amount double. And the spray droplet density was decreased as the droplet size was increased over 120 μm. The size of the most droplets deposited on target was under 180 μm. Therefore, those electrostatic nozzles designed were suitable for crops whose optimum biological size was 180μm or under 180μm.