静电喷雾的多喷头雾化特性及田间试验

Atomization characteristics of multi-nozzle electrostatic spray and field experiment

针对传统喷杆喷雾机作业时需水量大、叶片背面雾滴沉积量不足和雾滴分布不均匀等问题,该研究提出一种静电喷雾与喷杆喷雾相结合的施药技术。为探究静电喷杆喷雾机的最佳工作参数,明确不同参数对雾滴雾化效果的影响,利用Fluent软件建立了流场、离散雾场和空间电场耦合仿真模型。仿真试验结果表明,多喷头的空间电场分布均匀性优于单喷头,静电喷雾的雾滴体积中径比非静电喷雾减小12.7%。搭建静电喷雾试验平台,以喷雾水压、充电电压和喷头间距为试验因素,以雾滴的荷质比、粒径、分布均匀性和沉积量为试验指标进行雾滴的荷电特性和沉积特性试验。试验结果表明,多喷头喷雾的雾滴荷质比最大值为0.26 mC/kg,比单喷头喷雾提高52.9%,雾滴均匀性变异系数比非静电喷雾减小32.1%,体积中径减小14.8%,上、中、下层叶片正面的雾滴附着率分别提高27.1%、37.3%和45.2%;静电喷雾的最佳作业参数组合为充电电压6 kV、喷雾水压0.4 MPa和喷头间距250 mm。田间试验表明,静电喷头与常规喷头喷雾施药的病虫害防治效果基本一致,静电喷头的施药用水量减少了60%。在满足防控效果的前提下,静电喷雾能增加雾滴在植株下层和叶片背面的沉积量,有效减少田间作业的需水量,研究结果可为静电喷雾技术在大型喷杆喷雾机上的应用提供参考。

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 cm^2 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.