• Agricultural and Biosystems Engineering
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• v.3 no.1
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• pp.44-54
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• 2002

A brief review of current status in the field of agricultural spray and future research challenges are presented. Researches on the pesticides sprays, pollen sprays, postharvest sprays, and biological control agent sprays among the various applications of agricultural spray were selected and reviewed. In the agrochemical sprays, the techniques to increase the deposition such as electrospray and reduce the drift such as introductions of drift retardants and of mechanical means are reviewed. The introduction of mechanical means includes low drift, air-assisted, air inclusion, shield or shroud assisted and pulse flow nozzles. For flat fan nozzles, the data of breakup length and thickness of liquid sheet are essential to understand the atomization processes and develop the transport model to target In the air-assisted spray technology to reduce drift, further works on the effect of application height on drift and air assistance on droplet size should be followed. In addition, methods for quantifying the included air in the air inclusion techniques are required. The atomization characteristics of biopesticides spray are not being elucidated and the formulations of biopesticides should be taken into account the spray characteristics of existing nozzle and sprayer. A few researches on the droplet size of fallout can be found in the literature. A combined technology with electrostatic method into one of method for the reduction of drift may be an effective strategy for increasing deposition and reducing drift. Only an integrated approach involving all stakeholders such as engineers, chemists, and biologists, etc. can result in improved application of agricultural spray.

• Journal of ILASS-Korea
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• v.26 no.4
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• pp.189-196
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• 2021

Spray drift of agricultural nozzles has become a big issue because it causes low precision targeting and environmental pollution. In order to reduce the spray drift, study spray characteristics of agricultural nozzles is virtually important. In this study, shadowgraph and Mie-scattering visualization techniques were used to study the macroscopic spray and atomization characteristics of an agricultural nozzle. PDPA was used to measure the atomization characteristics of spray. The injection pressure is set to 1 bar, 3 bar and 5 bar, which covers the working range of the nozzle. For the PDPA experiment, 75 points were measured in an area of 160 mm × 120 mm at 10 mm intervals directly below the nozzle to grasp the overall atomization characteristics of the spray. It was found that the spray width and sheet width showed a linear correlation. As the injection pressure increased, the sheet expansion in the 0-degree direction and the sheet swing in the 90-degree direction jointly promoted the breakup of the sheet. In addition, the area close to the central axis had a large droplet velocity, and since a large droplet velocity promoted atomization of spray, the area close to the central axis had a smaller spray droplet diameter than the left and right regions.

• International Journal of Automotive Technology
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• v.4 no.3
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• pp.119-124
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• 2003

Dimethyl Ether (DME) is an excellent alternative fuel that provides lower particulate matter (PM) than diesel fuel under the same engine operating conditions. Spray characteristical of DME in common rail injection system were investigated within a constant volume chamber by using the particle motion analysis system. The injector used in this study has a single hole with the different orifice diameter of 0.2, 0.3 and 0.4 mm. The injection pressure was fixed at 35MPa and the ambient pressure was varied from 0.6 to 1.5 MPa. Spray characteristics such as spray angle, spray tip penetration and SMD (Sauter mean diameter) were measured. Spray angle was measured at 30d$_{0}$, downstream of the nozzle tip. The measured spray angie increased with increase in the ambient pressure. Increase of the ambient pressure results in a decrease of spray penetration. The experimental result, of spray penetration were compared with the predicted one by theoretical and empirical models. Increase in the ambient pressure and nozzle diameter results in an increase of SMD at a distance 30, 45 and 60d$_{0}$, downstream of the nozzle, respectively.ely.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.3
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• pp.27-36
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• 2018

Effective pesticide applications are needed to assure the quality and economic competitiveness of fruit production and lower the risk of spray drift. Experimental studies have shown that better spray coverage and less driftability require an understanding of the transport of spray droplets within turbulent airflows in the orchard and the interaction between droplet dynamics and tree canopies. This study developed a computational fluid dynamics (CFD) model to predict pesticide flows in the orchard and spray drift discharged from an air-assisted orchard sprayer. The model represented the transport of spray droplets as well as droplets captured by tree canopies, which were modeled as a conical porous model and branched tree model. Validation of the CFD model was accomplished by comparing the CFD results with field measurements. Spray depositions inside tree canopies and at off-target locations were in good agreement with the measurements. The resulting data presented that 38.6%~42.3% of the sprayed droplets were delivered to the tree canopies while 13.6%~20.1% were drifted out of the orchard, part of them reached farther than 200 m from the orchard. The study demonstrates that CFD model can be used to evaluate spray application performance and spray drift potential.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1997.06c
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• pp.74-79
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• 1997

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.569-576
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• 2023

An agricultural drones are gradually increasing in utilization due to economic efficiency, and consist of a main frame in charge of flying spray system in charge of moving pesticide to control targets. Therefore, the environment and characteristics of crops should be considered when controlling pesticides using drones and conditions such as systematic flying altitude of flight, speed, and spray time should be changed accordingly. However, pest control work using agricultural drones has different spray effects depending on level the operation proficiency and spray impact. In addition, there are variations in operating standards and control efficiency for agricultural drones, which hinder the distribution of agricultural control drones in the field of pest control work. Therefore, this study attempts to identify the spraying characteristics of agricultural drones, apply the effective spraying time, interval and experimentally verify the system that can calculation of spray area compared to previous studies. Through this experimental verification, it is intended to apply the optimal control process by minimizing the obstacles to pest control work by applying the operation method and systematic figures to agricultural drones.

• Journal of Biosystems Engineering
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• v.29 no.1
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• pp.21-28
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• 2004

Spraying is one of the most efficient methods for pesticide and insecticide control. Generally, orchard sprayers(aircarrier sprayer) are used for such applications. However, when an orchard sprayer is used, only 20% of total amount of spray deposits on the target. The rest of spray are not only wasted but are also potential sources of environmental pollution. The research far the development of electrostatic spraying system for orchard sprayer was conducted to develop the new pesticide application technology for the reduction of environmental pollution and f3r the production of safe agricultural products. The spray characteristics for nozzles with the different charging methods were tested and the effect of electrostatic charge was analyzed, in the laboratory experiments. The results of this study indicate that the capacitive type of electrostatic spraying nozzle exhibits a large current deposition of water sprays on the sample target. The covering area ratio by conventional spraying system was 10.2%, while that of electrostatic sprays with pulse induction charging method gave the increased covering area ratio by 4.3 times.

• Journal of Biosystems Engineering
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• v.35 no.4
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• pp.215-223
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• 2010

In order to develop an precision aerial pesticide application system to be attached to an unmanned helicopter which can be applied to small lots of land, this study analyzed the flowing and spraying characteristics of the spray droplets by the main rotor downwash by setting the application conditions at the flight altitude of 3 m, the diameter of main rotor of 3.1 m, the boom length of around 2.8 m, and the spraying rate of 8 L/ha. The results of this study are summarized below. Through analysis of the covering area ratio of the spray droplets by main rotor downwash by nozzle type, boom with tilt angle and height, it was found that the covering area ratio of the twin flat-fan nozzle of around 25% was more uniform than other types of nozzle, also boom with $10^{\circ}$ tilt angle and spraying height of 3 m was shown to be the appropriate conditions for aerial application of pesticides. It was found that the nozzle position to minimize the scattering loss of spray droplets due to vortex phenomenon at both ends of the main rotor was around 10 cm from the end of the main rotor. An application test for the aerial pesticide application system attached to the HUA-ACEI unmanned helicopter developed by the Rural Development Administration showed that the range of covering area ratio of the spray droplets was 10-25%, and the spraying width was approximately 7 m when over 10% of covering area ratio was considered for valid spraying.

• Journal of ILASS-Korea
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• v.8 no.4
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• pp.1-8
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• 2003

The objective of this study is to investigate experimentally atomization characteristics for differently made an ultrasonic twin-fluid nozzle. A spray system, an ultrasonic system, and three different type(Nozzle type, Tube type, Conventional type)are made and tested by applied with ultrasonic energy. In this investigation, the measurement and calculation of spray droplet are to analyze the effects of ultrasonic energy on the agricultural atomization system. Through the measurement of suray angle, spray column using, high speed camera and PDA, it is found that nozzle type is highest efficiency than that of tube type and conventional type. It was found that the ultrasonic energy increased the atomization efficiency of spray droplets about 9% respectively and spray angle was wide spray.

• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.454-460
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• 2019

The purpose of this study is to analyze the distribution characteristics of mist spray particle size by devising a rotary mist spraying device to develop the evaporative salt water desalination system. The rotary mist spraying device was consisted of a BLDC sirocco fan, a spinning fan, a fan fixed shaft and a salt water supply device etc. In this study we analyzed the characteristics of spray particle size and distribution according to the variation of sirocco fan surface roughness(Ra, ${\mu}m$), revolutions(rpm) and salt water flow rate(mL/min). When sirocco fan surface roughness(Ra) was in the range of $0.27{\sim}7.65{\mu}m$, the spray particle size was $0.117{\sim}1.360{\mu}m$. And then more than 90% of spray particles were found to be less than $0.50{\mu}m$. When sirocco fan surface roughness(Ra) was in the range of $12.70{\sim}22.84{\mu}m$, the spray particle size was $2.51{\sim}184.79{\mu}m$ and more than 98% of spray particles were found to be less than $13.59{\mu}m$. To analyze the effect of fan rotation speed on the size and distribution of spray particles, when surface roughness Ra was fixed $0.27{\mu}m$ and fan rotation speed and salt water flow rate was respectively changed at 3,800~5,600 rpm and 2.77~8.28 mL/min, spray particle size was $0.314{\sim}0.541{\mu}m$. And when salt water flow rate was 9.74 mL/min and fan rotation speed was 3,800~5,200 rpm, spray particle size was in the range of $29.29{\sim}341.46{\mu}m$ and in case of 5,600 rpm more than 98.23% of spray particles were in the range of $2.51{\sim}13.59{\mu}m$.