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Title: Air and spray mixture temperature effects on atomization of agricultural sprays

Author
item Hoffmann, Wesley
item Fritz, Bradley - Brad
item Martin, Daniel - Dan

Submitted to: Agricultural Engineering International: CIGR Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2011
Publication Date: 5/1/2011
Citation: Hoffmann, W.C., Fritz, B.K., Martin, D.E. 2011. Air and spray mixture temperature effects on atomization of agricultural sprays. Agricultural Engineering International: CIGR Journal. 13(1):Manuscript 1730.

Interpretive Summary: Drift of agrochemical sprays is highly dependent upon the physical properties of the spray solution that influence the generation (atomization) of spray droplets. This study examined effects of spray solution, solution temperature, and type on spray atomization in simulated high-speed aerial application conditions. The results of this study demonstrated that atomization characteristics of a specific spray solution were directly dependent upon the physical properties, which were in turn highly related to liquid temperature. The difference between air temperature and liquid temperature did not significantly affect spray atomization under aerial application conditions. The results will help applicators and researchers make consistent spray applications under different spray application conditions.

Technical Abstract: Spray drift associated with agrochemical operations is highly dependent upon the physical properties of the spray solution with respect to how they influence atomization. This study examined effects on spray atomization with two spray solutions across a wide range of solution temperatures for two nozzles spraying in high speed airstreams, which simulate aerial application conditions. The dynamic surface tension and viscosity of the spray solutions were also measured across the range of temperatures. Generally as the solution temperature increased, the dynamic surface tension and viscosity both decreased. This decrease in physical properties was directly related to the decrease in spray droplet size for all nozzles and airspeeds tested. Monitoring of spray solution temperature throughout the spray system of a typical agricultural aircraft demonstrated that while changes in the spray solutions temperature do occur, the range is much less than the ranges across which this atomization study covered. During a typical aerial application scenario, the temperature of a spray solution and the associated physical properties and atomization characteristics would not be expected to see significant variation.