Study On The Influence Of Environmental Parameters On Tlie Droplet Drift Of Multi-rotor P30 Plant Protection UAV

Environmental parameters are important factors that can not be ignored for droplet deposition and drift.The environmental parameters that affect droplet deposition and drift mainly include wind speed,temperature,humidity,and atmospheric stability.The wind speed is the most important environmental parameter that affects the quality of UAV spraying.In order to explore the influence of environmental parameters(mainly wind speed)to the spray droplet deposition and drift of plant protection drone,Kromekote paper,Mylar card and polyethylene wire were used as the droplet collection carrier.This paper studies the influence of wind speed on the deposition and drift of spray droplets at the period of one spray and three prevention in wheat field(18.8??27.5?)&wheat field weeding period before winter(5.0??13?).In this paper,we measure the drift of fog droplets at different locations in the downwind direction and established a drift buffer zone to provide theoretical guidance and data support for improving the efficiency of pesticide and reducing the drift of aerosol spray solution.The main research conclusions are as follows:(1)Analysis of sampling feasibility.Mylar card and polyethylene wire were used as the droplet collection carrier.Rhodamine-B was taken as tracer and operated by fluorescent test.The concentration absorption curve of the fluorescent tracer Rhodamine-B is:y=1626.5x-31.196,and the correlation coefficient R~2=0.9996.The average recoveries of Rhodamine-B on the deposition carrier Mylar card and polyethylene wire were79.25%?85.25%and 52.58%?60.24%,respectively.(2)To characterize the period of one spray and three prevention in wheat field and the situation of plant protection drone spray fog droplet deposition&drift,tests were taken at18.8??27.5?(normal temperature),wind speed was 0.1 m/s?4 m/s during test.The following results can be drawn by analyzing the sedimentary area:With different wind speeds,the average coverage of fog droplets in the deposition area is 1.48%?2.48%,the average fog droplet density is 9.2/cm~2?15.9/cm~2,and the average deposition amount is0.101?g/cm~2?0.179?g/cm~2.When the wind speed is 2.5m/s,deposition amount in the deposition area are most,and the deposition effect is the best.A certain wind speed is conducive to the deposition of fog droplets.When the wind speed is greater than or equal to2.5m/s,as the wind speed increasing,deposition amount of the deposition area will gradually decrease,and the initial position of the droplet in the deposition area will shift.With the wind speed increasing,the distribution uniformity of the mist droplet deposition in the deposition area is becoming worse.The following test results can be drawn by analyzing the drift zone:Wind speed has a significant effect on the coverage and density of droplets.When the wind speed is0.1m/s?4.0m/s,the drift ratio is 17.03%?68.9%,and the cumulative drift distance of 90%is 6m?21.5m,drift ratio increased with increasing wind speed.Therefore,when operating in an environment with a wind speed at 0m/s?4m/s,a drift buffer of at least 21.5m should be reserved.The cumulative drift of the droplets passing through the vertical sampling rack at 20m is 0?1.7%.The results show that the greater the wind speed,the higher the spatial penetration rate of the droplets at 20m.(3)To characterize wheat field weeding period before winter and the situation of plant protection drone spray fog droplet deposition&drift,tests were taken at 5.0??13?(low temperature),wind speed during test was 0.7m/s?3.7m/s.The following results can be drawn by analyzing the sedimentary area:The average coverage of fog droplets in the deposition area is 1.8%?3.6%,the average density of fog droplets is:9.68/cm~2?17.9/cm~2and the average deposit of fog droplets is0.254?g/cm~2?0.402?g/cm~2.The following test results can be drawn by analyzing the drift zone:wind speed is0.7m/s?3.7m/s,the fog drift rate is 23.91%?33.66%.When the wind speed change to1.1m/s?1.7m/s,fog droplets are still deposited at the furthest distance of 50m from the collection area.The result shows that humidity has a certain effect on the fine droplets.If the humidity is too high,the fine droplets float in the air and are not easy to settle,and it is easy to drift with the wind.Under test conditions,90%of the cumulative drift is within8m?16.5m.Therefore,at least 16.5m of drift buffer should be reserved.