Impact of Plugged Venturi Nozzle Air-Inclusion Ports on Droplet-Size Distribution

Abstract

Concern about pesticide drift has increased dramatically in recent years. An emphasis on increasing spray droplet size to mitigate off-target particle movement has occurred in response to this concern. Venturi nozzles were designed to create coarser droplets by entraining air within the spray solution in the nozzle body. In field applications, dirt, fertilizer, and other debris can plug air-inclusion ports. The objective of our research was to identify the impact of plugged air-inclusion ports on the droplet-size distribution of multiple venturi nozzles. The study was conducted using the low-speed wind tunnel at the Pesticide Application Technology Laboratory in North Platte, NE. Droplet-size distributions for five venturi nozzles and two orifice sizes (Air Induction [AI11004 and AI11006], Air Induction Extended Range [AIXR11004 and AIXR11006], Turbo TeeJet Induction [TTI11004 and TTI11006], Turbo Drop [TDXL11004 and TDXL11006], and Ultra Lo-Drift [ULD12004 and ULD12006]) were measured in combination with plugged or unobstructed air-inclusion ports, providing 28 total treatments. Measurements were made using a Sympatec HELOS-VARIO/KR laser diffraction system while testing water sprayed at 276 kPa. Similar patterns in droplet-size distribution within nozzles were observed across orifice sizes. When air-inclusion ports were plugged, the Dv0.1, Dv0.5, and Dv0.9 decreased for the AI and TDXL nozzles, remained relatively unchanged for the AIXR and ULD nozzles, and increased for the TTI nozzle. In addition, the percentage of fines less than 150 µm increased for the AI and TDXL nozzles, remained relatively unchanged for the AIXR and ULD nozzles, and decreased for the TTI nozzle when air-inclusion ports were plugged. This research helps to better understand the drift mitigation implications if debris were to plug venturi nozzle air-inclusion ports.

Spray particle drift mitigation using field corn (Zea mays L.) as a drift barrier

“…Droplet size data were subjected to analysis of variance in SAS (SAS v9.4; SAS Institute Inc., Cary, NC, USA) and comparisons among treatments were performed using Fisher's protected least significant difference (LSD) test ( P ≤ 0.05). DV 0.1 , DV 0.5 , DV 0.9 , and RS were analyzed with a gamma distribution, whereas the driftable fines response variable was analyzed with a beta distribution . Backtransformed data are presented for clarity.…”

“…DV 0.1 , DV 0.5 , DV 0.9 , and RS were analyzed with a gamma distribution, whereas the driftable fines response variable was analyzed with a beta distribution. 35,36 Backtransformed data are presented for clarity.…”

Particle drift potential of glyphosate plus 2,4-D choline pre-mixture formulation in a low-speed wind tunnel

“…This study was conducted in a low-speed wind tunnel at the Aerial Application Technology Laboratory located at the U.S. Department of Agriculture (USDA) Southern Plains Agricultural Research Center in College Station, TX (Butts et al 2018a;Hoffmann et al 2014a). Enlist Duo ® solution was prepared as previously described.…”

“…Despite efforts surrounding proper nozzle selection (Creech et al 2015;Dorr et al 2013), new herbicide formulations and adjuvants (Antuniassi et al 2016;Havens et al 2018;Hilz and Vermeer 2013;Kalsing et al 2018;Li et al 2013), new spraying techniques (Butts et al 2018c;Rodrigues et al 2018), and strategies to mitigate spray drift (Foster et al 2018;Ucar and Hall 2001;Vieira et al 2018a), 2,4-D remains a herbicide associated with drift and crop injury complaints (Egan et al 2014;Havens et al 2018). The hypothesis of this study was that differences in droplet size and droplet velocity could influence spray drift of Enlist Duo ® applications with venturi nozzles.…”

“…In general, droplets have their maximum velocity close to the nozzle and decelerate during transport to the target as a result of air resistance (Al Heidary et al 2014;Dorr et al 2013). Smaller droplets decelerate more rapidly due to aerodynamic drag (less kinetic energy) compared with larger droplets (Butts et al 2018a;Dorr et al 2013;Goering et al 1972;Nuyttens et al 2007Nuyttens et al , 2009. Despite the larger droplets generated by venturi nozzles, the droplets had slower initial velocities because of the pressure drop caused by the air-inclusion and preorifice components (Dorr et al 2013).…”