Chalendard, M. P.

Douzals, J. P.

English

JKI Open Journal Systems (Julius Kühn-Institut)

SuproFruit 2015 – 13th Workshop on Spray Application in Fruit Growing, Lindau, Germany, 15. – 18. July 2015  32 Julius-Kühn-Archiv, 448, 2015 Vertical and horizontal spray distribution of hollow cone nozzles in a wind tunnel. A preliminary study to mitigate spray drift in orchard applications.  J.P. Douzals, M.P. Chalendard  Irstea, UMR ITAP 365 Rue Jean-François Breton, F-34196 Montpellier, FRANCE  Introduction  Hollow cone nozzles are still widely used in orchard spray applications because of their small droplet sizes, visible sound coverage without air assistance on early vegetation stages. However, drift mitigation issues along water courses, sensitive crops and public areas generally imply the use of larger droplets generated by air injection hollow cone nozzles [Polveche et al., 2011]. This preliminary study aims at better defining the correlation between spray distribution patterns [Tamagnone et al, 2011] and drift curves both measured in IRSTEA wind tunnel equipped with a 9 m long distribution test bench. Vertical and horizontal spray orientations were compared with wind velocities of 0-2-4 and 5 m.s-1.  Materials and methods.  Nozzles  4 hollow cone nozzles from ALBUZ Company were tested: ATR Yellow, ATR Red, TVI Lilac, TVI Green, TVI Orange. Spray angle was 80°. Droplet sizes were measured by using a Dantec PDPA device (Power 2.5W, diffusion mode, 600 mm optics).  Table1 : Nozzle characteristics Nozzle type – injection pressure 10 bar  Flowrate (l.min-1) at 10 bars  VMD (μm)  ATR Yellow  1.03  143  ATR Red  1.72  173  TVI Lilac ISO 80-025  1.83  542  TVI Orange ISO 80 - 010  0.73  581  TVI Green ISO 80 – 015  1.10  702  Wind tunnel  All experiments were conducted in IRSTEA wind tunnel under temperature and air humidity control of 20°C and min. 90% respectively. Each modality (1 nozzle, 1 position, 1 pressure, 1 height) was tested 3 times (3 repetitions). Flow distributions were measured at 1 m height without any wind following 2 positions of nozzles. When wind speed is operated in the wind tunnel, sedimentation values are accumulated along the distance and the opposite value is calculated as a drift ratio [Douzals et al.,2014].  Results  Vertical distribution without wind (1 m height)  Fig 1a and 1b show the distribution patterns of tested nozzles in vertical and horizontal position. Recovery rates were found to vary from 93% (ATR Yellow, TVI Lilac), up to 97% (ATR Red, TVI Orange, TVI Green). Horizontal spray distribution patterns were logically found to be dependent on droplet size with expected differences between ATR and TVI nozzles.  SuproFruit 2015 – 13th Workshop on Spray Application in Fruit Growing, Lindau, Germany, 15. – 18. July 2015  Julius-Kühn-Archiv, 448, 2015 33  Fig 1a and 1b: Distribution patterns form horizontal spraying (1 m height) and correlation between droplet size and the peak distance  Drift measurements of Hollow Cone nozzles under windy conditions  Fig 2a introduces the relative drift obtained in the wind tunnel for a wind velocity of 4 m.s-1. (horizontal spraying) and Fig. 2b, the correlation between Dv50 and the drift ratio value at 5 m distance.   Drift ratio curves (Fig 2a.) are given as an example among the different wind speeds and nozzle orientation tested. A clear discrimination is observed between nozzle types (ATR vs TVI).  Conclusion  These preliminary results aimed at defining different hollow cone nozzles behavior on a distribution test bench with or without wind. When nozzles are oriented horizontally, the position (distance) where the peak occurs seems a relevant indicator of droplet size. Furthermore, when wind is applied, the spray pattern is modified but the drift ratio at a given distance is quite similar and also related to droplet size.  Acknowledgments  Authors are grateful to Albuz Company for their support and the Ministry of Agriculture (Etude sur l’optimisation de l’utilisation des pesticides et fertilisants, 2013).  References  Tamagnone M et al. 2011, Assessment of the influence of the sprayer operating parameters on the geometry of the spray generated by nozzles. 11th Suprofruit, Bergerac, France. CTIFL Ed., 58-59.  Douzals JP and AlHeidary M., 2014. How spray characteristics and orientation may influence spray drift in a wind tunnel, Aspects of Applied Biology 122, International Advances in Pesticide Application. 271-278. 

Vertical and horizontal spray distribution of hollow cone nozzles in a wind tunnel. A preliminary study to mitigate spray drift in orchard applications.

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Vertical and horizontal spray distribution of hollow cone nozzles in a wind tunnel. A preliminary study to mitigate spray drift in orchard applications.

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