Enhancing tunnel sprayer performance through optimization of constructional parameters.

A tunnel sprayer has distinct recycling systems, which save a significant portion of the applied pesticide. Its performance is directly or indirectly influenced by various constructional parameters of the recycling system (nozzle spacing, nozzle angle, tunnel opening, and fin pitch) because they influence the movement of spray droplets, characteristics of the droplets, and recycling rate of the system. Therefore, the effect of these parameters was investigated for improvement in the tunnel sprayer's performance. In this study, four adjustment mechanisms were developed for selected parameter's regulation and tested using a hybrid tree (artificial and natural leaf). The non-significant results of spatial spray distribution revealed its accuracy and potential ability for maintaining spray uniformity across the tree canopy, except in the central zone of both trees. By considering the poor spray deposits at the central zone of both trees, the statistical analysis was carried out for spray deposits maximization and recycling rate minimization. The spray deposits varied from 1.016 × 10 to 2.944 × 10 µg/mm and offered better plant protection. The sprayer saved up to 42.36% of the applied pesticide, which ensures economical farm operations and saves the environment. The optimized values for input parameters (i.e., X1: 350 mm, X2: 42.5 degrees, X3: 1100 mm, and X4: 41 mm) would improve the efficiency of the tunnel sprayer and conserve costly input resources.