风送喷雾辅助气流在果树冠层内分布机理研究

Applications of pesticides have ensured high quality products from the fruit industries. Although there are concerns about potential contamination of the environment caused by excessive use of pesticides. Air-assisted sprayer is widely used in orchard spraying applications. To fully meet the requirements for effective and efficient treatment of fruit, it is necessary to develop variable-rate spraying systems that deliver pesticides more economically, accurately and in an environmentally sustainable manner with minimum human involvement. This misdirected pesticide not only reduces the effectiveness of the application and wastes growers’money, it also increases the potential of environmental contamination... The five-port air-assisted sprayer will be used to do the operation experiment. The apple tree was used as research sample. To achieve the variable-rate flow rate based on tree structure, volume and foliage density, the magnitude of influence of tree structure, volume and foliage density on air velocity distribution inside canopies must be determined. Therefore, the research will include:1) To determine the flow rate spacial distribution in an open area from the air-assisted sprayer, to determine the influence of air velocity on droplet size distribution, to evaluate the relationship among airflow rate, droplet size and drift distance and determine the optimum distance between spray outlets and tree canopy. 2) To analyze the mechanism of airflow rate distribution inside canopy with different canopy structure, volume and foliage density from air-assisted sprayer, and to establish the air velocity distribution model inside canopy; to meet the requirement of pesticide application, the ranges of effective air velocity will be determined. 3) To evaluate the applicability of this model on the other small arbor trees, such as pear and orange trees. Finally, field tests will be conducted to evaluate models that compared to the sprayer without variable-rate air velocity system. These objectives were used to form a basis for the future development to control air flow rates for variable-rate sprayers.

为提高农药有效利用率，减少药液流失对环境的污染，风送式喷雾机广泛应用于果园植保施药。研究风送式果园喷雾机辅助气流变量控制是未来果园植保机械的发展方向。而有关辅助气流冠层内分布规律的研究尚未有报道。因此本项目拟以五指风送式果园喷雾机作为作业机械，以苹果树为代表的小乔木果树为研究对象，研究风送式果园喷雾机出口辅助气流流速空间分布规律，以及在不同辅助气流流速作用下雾滴粒径分布规律，分析辅助气流流速、雾滴粒径和雾滴飞行距离之间的关系，确定最佳喷雾距离；研究树冠生理特征参数（冠幅、体积、树叶密度）对辅助气流在果树冠层内分布规律的影响机理，确定满足作业效果的辅助气流有效作用范围，建立辅助气流在冠层分布规律模型；研究辅助气流在冠层内分布特性关系模型对于梨树和柑橘等其他类型小乔木果树的适用性，为实现风送式果园喷雾机辅助气流变量控制提供理论依据,推进我国果园植保施药机械和施药技术的发展与应用。

为提高农药有效利用率，减少药液流失对环境的污染，风送式喷雾机广泛应用于果园植保施药。研究风送式果园喷雾机辅助气流变量控制是未来果园植保机械的发展方向。而有关辅助气流冠层内分布规律的研究尚未有报道。本项目以五指风送式果园喷雾机械为作业机械，以苹果树为代表的小乔木果树为试验对象，研究了辅助气流空间分布规律及其作用下雾滴粒径分布规律，建立了辅助气流空间分布模型，研制了基于微距离成像技术的雾滴粒径测试系统；针对人工测量精度低、费时费力，而基于三维激光扫描技术、超声波技术等自然测量方法成本高、操作复杂的不足，提出了基于机器视觉的果树树冠体积测量方法，搭建了可移植性果树树冠体积自动测量 平台，完成对于果树树冠特征参数的提取，研究了辅助气流在冠层内的分布规律，建立了树冠特征信息（冠幅、体积、树叶密度）与辅助气流的数学模型，并验证了该模型对于梨树和柑橘等其他小乔木类果树的适用性。检测了喷雾机在变量作业条件下的喷雾作业效果，试验结果证明了通过调节风机进口内径改变喷雾机出口风速的方式是可行的，可以有效的提高雾滴的穿透能力，增加树叶的扰动，提高喷雾覆盖率，提高农药的有效利用率，有效的改善了喷雾效果。研制了一套室内喷雾三维移动平台，并针对多通道风送式喷雾机后盖风阻严重、风机消耗功率大等问题，优化了后盖弧形罩，改善了气流场的分布，提高了风机的效率，为实现风送式果园喷雾机辅助气流变量控制提供理论依据,推进我国果园植保施药机械和施药技术的发展与应用。