Evaluation of a pneumatic-shielded spraying system by CFD simulation

Shielding spray booms is one strategy recommended for reducing spray drift. Although many studies related to mechanical shields show positive effect on reducing spray drift, little information about the use of pneumatic shields is available. In this study, several pneumatic shield designs were rated based on drift potential by means of the FLUENT computational fluid dynamics (CFD) software package. For relative comparisons, conventional spraying using nozzles, air-assisted spraying, and air-shear spraying were included in the analysis. Results of this study indicate that not all simulated cases of pneumatic-shielded spraying provided better drift control. To ensure reduced drift potential and to reduce power required for pneumatic-shielded spraying, optimal operating parameters for the dominant variables appeared to be a jet velocity of 40 m s-1, a jet flow rate of 1.7 m3 s-1 m-1 of boom length, and a jet angle of 15° forward. Optimal operating parameters, obtained from analysis of variance, were similar to results from previous studies on air-assisted and air-shear spraying. Pneumatic-shielded spraying, with proper choice of operating parameters, may be a suitable alternative to reduce spray drift