Air and Spray Mixture Temperature Effects on Atomization of Agricultural Sprays

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 two spray solutions across a wide range of solution temperatures for two nozzles spraying into two high speed airstreams.  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.