Published in Transactions of the ASABE 58(2): 281-295 (doi: 10.13031/trans.58.10896). 2015 American Society of Agricultural and Biological Engineers. The current USDA-ARS aerial spray nozzle models were updated to reflect both new standardized measurement methods and systems as well as to increase operational spray pressure, aircraft airspeed, and nozzle orientation angle limits. The new models were developed using both central composite design and custom design response surface methodologies, which provide excellent fits to independently measured data (R2 values ranging from 0.81 to 0.99) for all droplet size parameters. The new models also updated the droplet size classification ratings by adopting a previously recommended set of nozzles and operational pressures that provide similar data to ASABE Standard Reference nozzles but are evaluated under aerial application conditions (primarily airspeed). Generally, for flat fan and deflection type nozzles, the new models result in increases to predicted DV0.1 data (droplet diameter at which 10% of the total spray volume is contained in droplets of equal or lesser diameter), decreases in DV0.5 and DV0.9 data (similar to DV0.1 but 50% and 90% of total spray volume), and increases in the percent of spray contained in droplets of 200 µm diameter or smaller. With straight stream nozzles, the DV0.1, DV0.5, and DV0.9 trends tend to be reversed. Droplet size classifications with the new models for flat fan and deflector type nozzles tend to shift ratings downward, as compared to the current models, with classes centered around fine and medium sprays. However, with straight stream nozzles, droplet size classifications tend to shift ratings upward as compared to the current models. The updated models will be used to populate spreadsheet and mobile device software-based user interfaces to provide aerial applicators with droplet size information for an increased range of nozzles and operational settings, allowing for better nozzle selection and operational guidance. Resources in this dataset:

Resource Title: Droplet Size Data File Name: All Data Fixed Wing Models 2014.csv Resource Description: Measured Droplet size data from the reported study.