Preliminary spray nozzle characterization activities through shadowgraphy at the AgroForestry Innovation Lab (AFI-Lab)

The AgroForestry Innovations Lab (AFI-Lab) of the Free University of Bolzano-Bozen (unibz), in synergy with local farmers and machine builders, is launching a research thread investigating sprayer performance and drift mitigation strategies in the context of South Tyrol, Italy. Nozzle characterization via Particle/Droplet Image Analysis (PDIA) is a stepping stone in this direction; the present work involves the use of an Oxford Lasers N60 shadowgraph to (i) gather a database of nozzle characteristics for future reference, (ii) interface the shadowgraph itself to custom Matlab code through the use of both raw and post-processed particle data, (iii) develop a methodology to evaluate nozzle performance, with a flexible approach toward the validation of future nozzle behaviour models, (iv) gathering expertise for internationally-recognized certification activities of new nozzles, and finally to (v) support and provide input for in-development sprayer performance models, aimed at drift prediction in support of wind tunnel activities for real-scale machine performance evaluation. A set of three conventional hollow-cone nozzles and their anti-drift equivalents have been analysed at two operating pressures in different portions of the cone. The results of the data acquisitions have been parsed and stored by an automated algorithm in Matlab and used to develop the code for the visualization and comparison of the droplet distributions. The work is closed with some remarks and future perspectives enabled by the choice of this type of instrument, especially the characterization of cone geometry and droplet density across the cone aperture.