梯形果园风送静电喷雾机仿真分析及试验

Simulation analysis and experiment of trapezoidal orchard air delivery electrostatic spray machine

针对传统果园喷雾机雾滴穿透性不足和叶片背面雾滴沉积量较少等问题,本研究结合静电喷雾技术自主设计了一种适用于Y型定向生长果树的梯形果园风送静电喷雾机.为优化果园静电喷雾机的工作参数,明确不同参数对雾滴雾化效果的影响,利用Fluent软件建立了空气流场、离散雾场和空间电场耦合仿真模型,仿真试验结果表明:雾滴充电过程主要集中在喷嘴电极附近,距离喷嘴电极越近,电场强度越大,离喷嘴越远,电场强度衰减速度越快,喷嘴20 mm范围内是最佳荷电区域,电极间距越小,空间电场强度叠加得越均匀,充电电压8 kV、喷头间距150 mm时,雾滴荷电效果最好,沉积量最大.本研究还以充电电压、出口风速和行驶速度为试验因素,进行了雾滴沉积性能试验,试验结果表明:随着充电电压的增大,雾滴在叶片的总体沉积量增加,雾滴穿透性明显加强,增大出口风速雾滴沉积量总体呈先增大后减小的趋势,出口风速20 m·s-1时,雾滴沉积效果最好,且通过多因素方差分析得出试验中设置的参数对雾滴沉积量的影响大小顺序为喷雾距离、出口风速、充电电压、行驶速度,田间试验结果与仿真结果基本一致.

To solve the problems of the traditional orchard sprayer with the lack of droplet penetration and the small amount of droplet deposition on the back of blade, the trapezoidal orchard air delivery electrostatic sprayer was independently designed for Y-shaped directional growth fruit trees by electrostatic spray technology. To optimize the working parameters of the orchard electrostatic sprayer and clarify the influence of parameters on the atomization effect of droplets, the Fluent software was used to establish the coupling simulation model of air flow field, discrete fog field and space electric field. The simulation test results show that the droplets charging process are focused on electrodes near the nozzle. The closer the distance to the nozzle electrode is, the greater the electric field intensity is. The farther the distance from the nozzle is, the faster the electric field intensity attenuation is. The best charged area is 20 mm away from nozzle. With the decreasing of electrode gap, the space superposition of electric field intensity becomes more uniform.Under the conditions with charging voltage of 8 kV and nozzle distance of 150 mm, the best droplets charge effect can be achieved with the largest deposition amount. Taking charging voltage, wind speed and speed as test factors, the droplet deposition performance test results show that with the increasing of charging voltage, the overall deposition quantity of droplets in the blade is increased, and the penetrability of droplet is significantly strengthened. With the increasing of export wind speed, the overall deposition quantity of droplets is increased firstly with latter decreasing. When the export wind speed is 20 m·s-1, the best droplet deposition is obtained. The decreasing effect sequence of parameters in the experiment on droplet deposition is spray distance, export wind speed, charging voltage and speed.The result of field test is basically consistent with that of simulation.