果园在线混药型静电喷雾机的设计与试验

为提高果园轻型机动喷雾机的作业性能，设计了一种果园在线混药型静电喷雾机，进行了混药均匀性与稳定性试验和静电喷雾沉积试验。试验测得混药均匀性和混药稳定性的最大变异系数分别为4.46%和3.51%。采用风辅静电喷雾方式的无冠层采样架上采样点正面的雾滴附着率相对于无风辅无静电喷雾方式分别提高了9.3%、46.3%和53.2%，采样点反面的雾滴附着率分别提高了82.9%、164.3%和184.2%。风辅静电喷雾下在仿真柑橘树冠层内部叶片正面的雾滴附着率为48个/cm2左右，叶片反面为37个/cm2，相对于无风辅无静电方式分别提高了166.7%和428.6%。试验结果表明：所设计的在线混药系统具有良好的混药性能，风辅静电式喷雾系统可提高雾滴吸附能力和穿透能力，能够满足25个/cm2的病虫害防治附着率要求。该研究为果园喷雾机的机构设计和性能优化提供参考。

Design and experiment of an electrostatic sprayer with online mixing system for orchard

Abstract: In order to optimize the spraying performance of orchard light self-propelled sprayer, an orchard electrostatic sprayer with online mixing system was developed. The online mixing system had several advantages compared to manual mixer and mechanical premix system. The safer operating conditions, reducing waste production and improving mixing performance were the main features. Sprayer was equipped with induction charging spray nozzles to obtain the enhanced adhesion and deposition. Compared with corona charging and contact charging, induction charging had several advantages such as lower working voltage, easier electrode insulation and smaller current capacity. The electrostatic sprayer was equipped with an air support system to produce additional atomization and improve deposition uniformity by assisting the transport of spray towards the target. The design of air-assisted electrostatic nozzles could prevent the charged droplets from wetting the electrodes and thereby keep the electrodes dry. The spray booms could be adapted to the shape of the individual plants. The mixing uniformity and stability were evaluated experimentally under the conditions that the mixture proportion of 0.1%, 0.2% and 0.3% and the sprayer pressure of 0.50, 0.75 and 1.00 MPa. Experiments were carried out to evaluate the droplet deposition of air-assisted electrostatic spraying system and non-air-assisted electrostatic spraying system, and compare the droplet adhesion rates in the deposition shelf and the interior of artificial tree canopy with electrostatic voltage of 8 kV and outlet wind speed of 27.6 m/s. The measured maximum variable coefficients of mixing uniformity and stability were 4.46% and 3.51% respectively. With air-assisted electrostatic spraying system, the droplet adhesion rates in the upper side of the deposition shelf were 94, 98 and 72 /cm2 respectively at the sampling distance of 0.5, 0.8 and 1.1 m, which increased by 9.3%, 46.3% and 53.2% respectively compared to those of non-air-assisted electrostatic spraying system. The droplet adhesion rates in the bottom side of the deposition shelf were 75, 74 and 54 /cm2 respectively, which increased by 82.9%, 164.3% and 184.2% respectively compared to those of non-air-assisted electrostatic spraying system. The droplet adhesion rates in the upper and bottom side of the interior of artificial tree canopy were 48 and 37 /cm2 respectively with air-assisted electrostatic spraying system, which increased by 166.7% and 428.6% respectively compared to those of non-air-assisted electrostatic spraying system. The results indicate that the proposed online mixing system has good mixing performance. The air-assisted electrostatic spraying system can improve the performance of spray deposition and spray penetration, which can meet the requirement of droplet adhesion rate over 25 /cm2 in the application of pest and disease control. These results also show that it is feasible to improve the deposition performance by using the proposed charging technology with air support system, which can provide a reference for the design of orchard sprayer mechanism and the optimization of spray performance.