Spray drift characteristics test of unmanned aerial vehicle spray unit under wind tunnel conditions

Wang, Changling; Zeng, Aijun; He, Xiongkui; Song, Ji Hyeon; HERBST, Andreas; Gao, Wanlin

doi:10.25165/j.ijabe.20201303.5716

Cited by 21 publications

(17 citation statements)

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“…The relative span (RS) results ranged from 1.29 to 1.42 and no significant difference was found between pressures. V75, V100 and V200, useful parameters for assessing the spray drift potential in a few previous studies, [38][39][40] all showed a significant rise when the pressure increased. For all tested pressures, most of the sprayed droplets had a diameter smaller than 200 μm (77.2-91.9%) and volume fractions of droplets smaller than 75 and 100 μm ranged from 13.2% to 30.1% and 27.0% to 51.2%, respectively.…”

Section: Droplet-size Spectrummentioning

confidence: 99%

Spray performance evaluation of a six‐rotor unmanned aerial vehicle sprayer for pesticide application using an orchard operation mode in apple orchards

Wang

Liu

Zhang

et al. 2022

Pest Management Science

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BACKGROUND: In the last decade, unmanned aerial vehicle (UAV) sprayers have been growing rapidly worldwide as a new method for pesticide application, especially in Asian countries. More and more manufacturers and service providers are currently aiming at UAV spraying operation for fruit trees with higher economic value. We evaluated the spray performance of an electric six-rotor UAV sprayer using an orchard operation mode (different application volumes and flight patterns) in a hilly apple orchard with small and sparse trees (SS) and a plain orchard with tall-spindle trees (TS).RESULTS: Application volume (APV) had a significant influence on the spray coverage parameters in both orchards, while flight pattern, intra-row, inter-row and verti-row, had a relatively limited influence at 60 0 and 85 7 L/ha. The UAV's downwash airflow produced a good spray penetration in the isolated SS trees, but not for the conjoined TS trees. It is better to fly along and above rows at 63.5 L/ha or higher for SS trees. The excessively low underside coverage is the main drawback of UAV orchard pesticide application and the underside droplet size was generally less than 200 ∼m.CONCLUSION: Spray performance is closely related to tree shape, planting pattern, UAV payload, application volume, spray droplet size and downwash airflow field. The results provide data support for the best operational practice development and the decision model for the application volume of UAV sprayer orchard operations. The underside spray performance requires further improvement by several effective measures.

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Section: Droplet-size Spectrummentioning

confidence: 99%

Spray performance evaluation of a six‐rotor unmanned aerial vehicle sprayer for pesticide application using an orchard operation mode in apple orchards

Wang

Liu

Zhang

et al. 2022

Pest Management Science

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“…Considering spraying characteristics, in addition to the difference of application rate between ground- and UAV-based application, droplets of UAV spraying need to travel a longer distance before depositing on target crops, which might increase droplet drift potential ( Wang et al, 2020 ). Hence, it is an essential thing to improve droplet distribution in the target area when UAVs are employed as sprayers.…”

Section: Introductionmentioning

confidence: 99%

UAV spraying on citrus crop: impact of tank-mix adjuvant on the contact angle and droplet distribution

Meng

Zhong

Liu

et al. 2022

PeerJ

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Adding tank-mix adjuvants into the spray mixture is a common practice to improve droplet distribution for field crops (e.g., rice, wheat, corn, etc.) when using Unmanned Aerial Vehicle (UAV) sprayers. However, the effectiveness of tank-mix adjuvant for UAV spraying in orchard crops is still an open problem, considering their special canopy structure and leaf features. This study aims to evaluate the effects of a typical tank-mix adjuvant concentrations (i.e., Nong Jian Fei (NJF)) on Contact Angle (CA) and droplet distribution in the citrus tree canopy. Three commonly used parameters, namely dynamic CA, droplet coverage, and Volume Median Diameter (VMD), are adopted for performance evaluation. The dynamic CAs on the adaxial surface of citrus leaves, for water-only and NJF-presence sprays, respectively, are measured with five concentration levels, where three replications are performed for each concentration. The sprays with 0.5‰ NJF are adopted in the field experiment for evaluating droplet distributions, where Water Sensitive Papers (WSPs) are used as collectors. Two multi-rotor UAVs (DJI T20 and T30) which consist of different sizes of pesticide tanks and rotor diameters are used as the spraying platforms. Both water-only and NJF-presence treatments are conducted for the two UAVs, respectively. The results of the CA experiment show that NJF addition can significantly reduce the CAs of the sprays. The sprays with 0.5‰ NJF obtain the lowest CA within the observing time, suggesting a better spread ability on solid surface (e.g., WSPs or/and leaves). With respect to the effects of NJF addition on individual UAVs, the field trial results indicate that NJF addition can remarkably increase both the droplet coverage and VMD at three canopy layers, except for T30 droplet coverage of the inside and bottom layers. Comparing the difference of droplet coverage between two UAVs, while significant difference is found in the same layer before NJF addition, there is no notable difference appearing in the outside and bottom layers after NJF addition. The difference of VMD in the same layer between two UAVs is not affected by NJF addition except for the bottom layer. These results imply that the differences of droplet coverage among different UAVs might be mitigated, thus the droplet distribution of some UAVs could be improved by adding a tank-mix adjuvant into the sprays. This hypothesis is verified by investigating the droplet penetration and the correlation coefficient (CC) of droplet coverage and VMD. After NJF addition, the total percentage of T20 droplet coverage in the bottom and inside layers is increased by 5%. For both UAVs, the CCs indicate that both droplet coverage and VMD increase at the same time in most cases after NJF addition. In conclusion, the addition of a tank-mix adjuvant with the ability to reduce CA of the sprays, can effectively improve droplet distribution using UAV spraying in the citrus canopy by increasing droplet coverage and VMD.

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“…Here we mainly discussed the relationship between particle size and droplet deposition. According to the results of wind tunnel experiments to test droplet deposition with different types of nozzle parameters, a larger droplet size had a better performance on anti-drift and droplet deposition ( Wen et al, 2016 ; Wang C. et al, 2020 ). Zhang et al (2018) established a CFD model to study the relationship between droplet size and droplet drift under crosswind conditions.…”

Section: Unmanned Aerial Vehicle Operation Parameters Affecting the D...mentioning

confidence: 99%

Research on Methods Decreasing Pesticide Waste Based on Plant Protection Unmanned Aerial Vehicles: A Review

Kaizu

Huang

et al. 2022

Front. Plant Sci.

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In plant protection, the increasing maturity of unmanned aerial vehicle (UAV) technology has greatly increased efficiency. UAVs can adapt to multiple terrains and do not require specific take-off platforms. They do well, especially in farmland areas with rugged terrain. However, due to the complex flow field at the bottom of a UAV, some of the droplets will not reach the surface of a plant, which causes pesticide waste and environmental pollution. Droplet deposition is a good indicator of the utilization rate of pesticides; therefore, this review describes recent studies on droplet deposition for further method improvement. First, this review introduces the flight altitude, speed, and environmental factors that affect pesticide utilization efficiency and then summarizes methods to improve pesticide utilization efficiency from three aspects: nozzles, electrostatic sprays, and variable spray systems. We also point out the possible direction of algorithm development for a UAV’s precision spray.

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Spray drift characteristics test of unmanned aerial vehicle spray unit under wind tunnel conditions

Cited by 21 publications

References 0 publications

Spray performance evaluation of a six‐rotor unmanned aerial vehicle sprayer for pesticide application using an orchard operation mode in apple orchards

Spray performance evaluation of a six‐rotor unmanned aerial vehicle sprayer for pesticide application using an orchard operation mode in apple orchards

UAV spraying on citrus crop: impact of tank-mix adjuvant on the contact angle and droplet distribution

Research on Methods Decreasing Pesticide Waste Based on Plant Protection Unmanned Aerial Vehicles: A Review

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