单旋翼无人机作业高度对槟榔雾滴沉积分布与飘移影响

Effects of Working Height of Single-rotor Unmanned Aerial Vehicle on Drift and Droplets Deposition Distribution of Areca Tree

为了阐明3WQF120-12型单旋翼无人植保机喷施槟榔树的雾滴沉积效果、地面流失雾滴沉积分布、飘移及可应用性,研究了无人机不同作业高度对槟榔树冠层及地面喷施效果的影响。试验选用诱惑红染色剂,并配制成质量分数为0.5%的水溶液,代替农药;用铜版纸进行雾滴采集,并利用图像处理软件DepositScan分析得出雾滴沉积结果。结果表明:作业高度对槟榔树各层采样点的雾滴沉积量没有显著性影响,同一高度作业时,树冠上层与树冠下层、树冠上层与树果层之间的雾滴沉积量有显著差异,树冠上层雾滴沉积水平最高可达53.27%,树冠下层和树果层可达树冠上层的59.19%和27.91%;地面流失采样点雾滴沉积结果显示,不同作业高度对地面3列采样点的雾滴沉积量有显著性影响,最低平均沉积水平约19.9%;飘移区数据显示,3个作业高度对飘移带采样点的雾滴沉积量没有显著性影响,当作业高度为12.09 m时,飘移带测得的飘移量最大,作业高度10.40 m时飘移量最小。同时测试发现,飘移距离最远可达36.35 m,因此实际作业时必须留出足够的安全距离。

Aiming to elucidate the effects of 3WQF120-12 single-rotor unmanned aerial vehicle(UAV)on the effect of droplet,deposition distribution,ground loss droplets,drift,and applicability when spraying areca palm.The impact of different working heights of UAV on the spraying effect of areca palm canopy was mainly studied.In this experiment,the red stain aqueous solution with a mass fraction of 0.5%was selected and instead of pesticides.The droplets were collected on coated paper and analyzed by an image processing software(DepositScan).The results showed that when the operation height was 12.09 m,11.46 m and 10.40 m,respectively,the operation height had no significant influence on the droplets deposition amount of the sampling points in each layer of the areca palm.Meanwhile,the deposition level in the upper canopy could reach 53.27%,that of the lower canopy and fruit layer can reach 59.19%and 27.91%of the upper canopy.The results of the droplets deposition at the ground loss sampling points showed that the droplets deposition of the three column sampling points on the ground was significantly affected by different operation heights.When the operation height was 10.40 m,the droplets loss on the ground was the least,and the average deposition level was about 19.9%.The data of the drift area showed that the three working heights had no significant influence on the droplets deposition of the sampling points in the drift line.When the working height was 12.09 m,the drift line sample location measured the largest amount of drift and the working height of 10.40 m had the smallest.At the same time,it was found that the downwind distance corresponding to 90%drift accumulation could reach as far as 36.35 m.Therefore,sufficient safety distance must be left for practical operation.The areca aerial spraying was very different from that of conventional crops,mainly in working speed and height.The speed of areca aerial spraying was about 1.5 m/s,which was much lower than usual speed(3~5 m/s),and the working height can usually be more than 10 m.The wake vortices were mainly influenced by working height,as the working height increased,the amount of droplets deposition was decreased,especially in the upper layer of the areas’canopy.Due to the operation speed was slow,the acting time of the rotor wind field was relatively long.The combined action of downwash airflow and crosswind in the rotor wind field can significantly improve the penetration of droplets.In this experiment,there were three different working heights,and the droplet volume median diameter(VMD)of droplets in each layer was changed significantly with the working heights.With the increase of crosswind and working height,the droplet volume median diameter(VMD)of droplets in each layer was decreased,and the mean deposition and percent area coverage rate in the fruit layer could increase by up to 53.75%and 62.20%,respectively.In actual operations,appropriate operation parameters can be selected according to the growing period and the occurrence part of diseases and pests.