Volume 5, Issue 6 (June 2008)

    Spray Adjuvant Effects on Droplet Size Spectra Measured by Three Laser-Based Systems in a High-Speed Wind Tunnel

    (Received 16 May 2007; accepted 29 April 2008)

    Published Online: 2008

    CODEN: JAIOAD

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    Abstract

    Spray droplet size has long been recognized as the most important variable that aerial applicators can influence to mitigate spray drift from the application site. There are several different technologies that are used by researchers to measure droplet size from spray nozzles. The objective of these studies was to determine the influence of eight spray adjuvants on the droplet size spectrum produced by two nozzles in a high-speed wind tunnel when characterized using three different droplet size measurement systems. The adjuvant, nozzles, and airspeeds used in these studies are commonly used by aerial applicators. Three droplet sizing systems (Malvern laser diffraction, PMS optical array probe, and LaVision laser imaging) were simultaneously operated to measure the spray droplet size spectra for each adjuvant, airspeed, and nozzle combination. Two spray nozzles (a D6-46 nozzle and a D2 straight stream nozzle) were evaluated in a high-speed wind tunnel at airspeeds of 45 and 58 m/sec. There were significant differences in the droplet size spectra produced by the eight spray adjuvants tested. There were also significant differences between the droplet size values reported by the three measurement systems (Malvern, LaVision, and PMS) evaluated; however, there was considerable agreement trendwise. In general, the Malvern reported smaller spray droplet size spectra values than the LaVision, while the PMS system generally reported the largest spray droplet size spectra values. These tests are the first reported studies where all three droplet sizing systems were operated simultaneously.


    Author Information:

    Hoffmann, W. Clint
    Agricultural Engineer, USDA-ARS-Areawide Pest Management Research Unit, TX

    Hewitt, A. J.
    Director, Centre for Pesticide Application and Safety and Centre for Spray Technology Application Research and Training, University of Queenland, Gatton,

    Ross, J. B.
    Entomology Specialist, New Mexico State University, Las Cruses, NM

    Bagley, W. E.
    Product Manager, Wilbur-Ellis Company, San Antonio, TX

    Martin, D. E.
    Agricultural Engineer, USDA-ARS-Areawide Pest Management Research Unit, TX

    Fritz, B. K.
    Agricultural Engineer, USDA-ARS-Areawide Pest Management Research Unit, TX


    Stock #: JAI101233

    ISSN: 1546-962X

    DOI: 10.1520/JAI101233

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    Author
    Title Spray Adjuvant Effects on Droplet Size Spectra Measured by Three Laser-Based Systems in a High-Speed Wind Tunnel
    Symposium Pesticide Formulations and Delivery Systems: 26th Volume, 2005-10-20
    Committee E35