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United States Department of Agriculture

Agricultural Research Service

Research Project: ECOLOGICALLY BASED MANAGEMENT OF BOLL WEEVILS AND OTHER ROW CROP PESTS UNDER TRANSITION TO BOLL WEEVIL ERADICATION IN TEMPERATE REGIONS

Location: Insect Control and Cotton Disease Research Unit

Title: Airspeed and orifice size affect spray droplet spectra from an aerial electrostatic nozzle for rotary-wing applications

Authors
item MARTIN, DANIEL
item Carlton, James -

Submitted to: Atomization and Sprays
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 2, 2013
Publication Date: April 30, 2013
Citation: Martin, D.E., Carlton, J.B. 2013. Airspeed and orifice size affect spray droplet spectra from an aerial electrostatic nozzle for rotary-wing applications. Atomization and Sprays. 22:997-1010.

Interpretive Summary: The aerial electrostatic spray system patented by the USDA-ARS is a unique aerial application system which charges spray particles for the purpose of increasing deposition and efficacy of crop protection products. While this system has many potential benefits, very little is known about how changes in airspeed or nozzle orifice size affect droplet size of electrostatically charged sprays. Laser data collected in a high-speed wind tunnel showed that increases in airspeed produced smaller spray droplets for all nozzle sizes tested. And generally, a decrease in nozzle orifice size increased the fineness of the spray droplet spectra at all airspeeds but also increased the charge-to-mass ratio of the spray, which can improve spray deposition. The results from this study will help aerial applicators better understand how changes in rotary-wing airspeeds and nozzle orifice size affect droplet size from aerial electrostatic nozzles, which can help improve deposition and reduce off-target drift.

Technical Abstract: The aerial electrostatic spraying system patented by the USDA-ARS is a unique aerial application system which inductively charges spray droplets for the purpose of increasing deposition and efficacy. While this system has many potential benefits, no published data exits which describe how changes in airspeed or nozzle orifice size affect the droplet spectra of charged sprays at rotary-wing airspeeds. This study quantified these effects in a controlled wind tunnel at airspeeds from 80-177 km/h. These tests were conducted at the USDA-ARS Aerial Application Technology research facilities in College Station, Texas. Laser diffraction data showed that increases in airspeed produced smaller spray droplets for all nozzle orifices tested, as quantified by standard spray droplet parameters. Generally, a decrease in nozzle orifice size increased the fineness of the spray droplet spectra at all airspeeds but also increased the charge-to-mass ratio of the spray, which can improve spray deposition. The results from this study will help aerial applicators better understand how changes in rotary-wing airspeeds and nozzle orifice size affect droplet size from aerial electrostatic nozzles.

Last Modified: 9/29/2014
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