A new integrated CFD modelling approach towards air-assisted orchard spraying—Part II: Validation for different sprayer types

Endalew, Ayenew Melese; Debaer, C.; Rutten, N.; Vercammen, J.; Delele, Mulugeta Admasu; Ramón, Herman; Nicolaı̈, Bart; Verboven, Pieter

doi:10.1016/j.compag.2009.11.007

Cited by 47 publications

(28 citation statements)

References 17 publications

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“…Generally, the average jet velocity magnitude at the (c); where u, v and w, are the jet velocity components along the jet (x-direction), vertical (y-direction) and across the jet (z-direction), respectively. Also presented in Endalew et al (2010b)) outlet for the AirJet Quatt was lower than that of the Duoprop. While u at most of the vertical positions was less than 20 m s −1 for the AirJet Quatt, it was greater for the Duoprop.…”

Section: Experimental Site and Measurementsmentioning

confidence: 69%

“…1a, b). As reported in Endalew et al (2010b), Fig. 3 shows the vertical profiles of the jet velocity components measured near the jet outlet and extrapolated at the jet outlet for the three sprayers.…”

Section: Experimental Site and Measurementsmentioning

confidence: 98%

“…The solid lines and solid circles are values for fully-leafed trees whereas the dotted lines and circles are for leafless trees both behind the canopy at position A. The measured and simulated peak velocities were linked both in space and time as reported in Endalew et al (2010b). Since the presence of the canopy, as well as leaves before the canopy at position C (Figs.…”

Section: Model Evaluationmentioning

confidence: 99%

“…These sprayers are designed for the spraying of agricultural plant protection products in orchards on medium to large size trees. The detailed description of these sprayers can be found in Endalew et al (2010b).…”

Section: Description Of the Sprayersmentioning

confidence: 99%

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Modelling the Effect of Tree Foliage on Sprayer Airflow in Orchards

Endalew

Debaer²,

Rutten³

et al. 2010

Boundary-Layer Meteorol

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The effect of tree foliage on sprayer airflow through pear trees in a fruit orchard was studied and modelled in detail. A new three-dimensional (3-D) computational fluid dynamics model that integrates the 3-D canopy architecture with a local closure model to simulate the effect of the stem and branches and leaves of trees separately on airflow was developed. The model was validated with field observations made in an experimental orchard (pcfruit, Sint-Truiden, Belgium) in spring and summer 2008 and was used to investigate the airflow from three air-assisted orchard sprayers (Condor V, Duoprop and AirJet quatt). Velocity magnitudes were measured before and behind leafless and fully-leafed pear canopies across the row while the operating sprayers are passing along the row, and were compared with the simulations. The simulation results predicted the measured values well with all the local relative errors within 20%. The effect of foliar density on airflow from the three air assisted sprayers was manifested by changing the magnitude and direction of the sprayers' air velocity behind the canopy, especially at the denser regions of the canopy and by changing the pattern of velocity decay horizontally along the jet. The developed methodology will also allow a thorough investigation of atmospheric airflow in canopy structures.

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Section: Experimental Site and Measurementsmentioning

confidence: 69%

Section: Experimental Site and Measurementsmentioning

confidence: 98%

Section: Model Evaluationmentioning

confidence: 99%

Section: Description Of the Sprayersmentioning

confidence: 99%

See 2 more Smart Citations

Modelling the Effect of Tree Foliage on Sprayer Airflow in Orchards

Endalew

Debaer²,

Rutten³

et al. 2010

Boundary-Layer Meteorol

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“…The DDM 1000 cross flow sprayer was equipped with an air tower and ultrasonic sensors (UM30-1_111/5, Sick, Germany). Distance between sensors and nozzles was 2.15 m. According to this and considering a forward speed of 6 km h -1 (1.66 m s -1 ) it was estimated that a delay of sensors detection and nozzles activation would be 1.1 s and nozzles deactivation 1.3 s. Equipping the sprayer with an air-tower produces a horizontal air flow towards the canopy (Endalew et al, 2010) with the aim of improving spray deposition and reducing spray drift (Fox et al, 1992;Holownicki et al, 2000). The ultrasonic sensors were used for tree identification (Fig.…”

Section: Spray Application Techniques and Methods Of Calibrationmentioning

confidence: 99%

Quality and efficiency of apple orchard protection affected by sprayer type and application rate

Sedlar

Bugarin

Nuyttens³

et al. 2013

Span. j. agric. res.

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The goal of this work was to evaluate the potential of reduced application rates in apple trees as well as the potential of selective spray applications by using sensor-based tree detection techniques in Serbian fruit production. Their economical and biological effect was evaluated based on the quality and efficiency of the crop protection and technoeconomic analysis. Results showed that during suitable weather conditions and with properly adjusted sprayer settings, a reduced application rate of 381 L ha -1 gave same quality of crop protection as a medium application rate of 759 L ha -1 . A two-year efficiency trial on Venturia inaequalis and Podosphaera leucitricha infecting apple also showed that there was no significant difference in crop protection results for different types of orchard application techniques and application rates. The techno-economic analysis showed that selective application should be introduced in practice in areas > 3 ha given that the cost of their introduction pays off after 2-3 seasons. Every subsequent season would give a clear economic profit. Besides the economic benefits, selective application technique also has a significant positive ecological effect due to reduction of spray losses and the amount of plant protection products used.

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Air‐assisted sprayers

2014

Pesticide Application Methods

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The provision of an airflow to assist in the distribution of pesticides within crop canopies has led to a number of sprayer designs with different fan systems and configurations of a range of nozzle types. Generally, the interest in the use of air-assisted sprayers has increased since Potts (1958) recognised the ability to reduce spray volumes significantly by using an airflow to project droplets into a crop canopy. Traditionally used for treating tree crops, air-assisted sprayers have now been adopted in many other types of crop. Downwardly directed air assists droplet penetration of arable field crop canopies and in reducing downwind drift (Figure 8.1).However, registration authorities are concerned that when spraying orchards, small droplets can drift above the tree canopy (Gil et al., 2007(Gil et al., , 2008 and outside orchards so buffer zones are wider for this type of application. Reyes et al. (2012) have developed a data acquisition system to assess the quality of spraying and verify whether the weather conditions were appropriate when a spray was applied.Various terms have been used in association with air-assisted spraying. These include 'concentrate', 'mistblower' and 'air-carrier' spraying. Mistblowers are sprayers that produce droplets in the 50-100 μm size range as these droplets are most effectively conveyed within an airstream. Potts (1958) found that in a particular airstream, droplets of 60-80 μm diameter were carried 46 m, while the larger 200-400 μm droplets travelled only 6-12 m. Larger droplets will be influenced more by gravity, while the smallest droplets are less likely to impact on foliage and other targets as they remain within the airstream. This is particularly important when projecting spray upwards into a tree canopy as fall-out due to gravity can result in considerable wastage of pesticide on the ground as well as increasing risk of operator exposure to the pesticide. However, with greater concern about spray drift out of orchards, coarser sprays are increasingly selected. The distance that large droplets are transported depends very much on the strength of the air assistance and the initial direction of trajectory of the droplets. As the risk of spray drift from orchards is considered to be greater than from arable crops, the unsprayed buffer zone (UBZ) in the UK is at least 18 m, although when using a tunnel sprayer, this is reduced to 5 m.

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A new integrated CFD modelling approach towards air-assisted orchard spraying—Part II: Validation for different sprayer types

Cited by 47 publications

References 17 publications

Modelling the Effect of Tree Foliage on Sprayer Airflow in Orchards

Modelling the Effect of Tree Foliage on Sprayer Airflow in Orchards

Quality and efficiency of apple orchard protection affected by sprayer type and application rate

Air‐assisted sprayers

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