Background: The air-induction nozzle greatly reduces drift potential by increasing spray droplet size compared with a standard flat-fan nozzle. The current study aims to reveal the mechanism behind the formation of large droplets through the air-induction nozzle from the aspect of bubble evolution in the spray sheet.
Results: Bubble break-up leads directly to the formation of perforations because large bubbles reach both sides of the spray sheet. The surface disturbance induced by bubble break-up modulates spray sheet thickness, which indirectly leads to the generation of perforations. Compared with the spray pressure, nozzle configuration has a more significant effect on both the volumetric flow rate of intake air and the thickness of the spray sheet. As the nozzle is changed from ID-120-01 to ID-120-05, the volumetric flow rate of intake air increases by 801.30% at a spray pressure of 0.3 MPa, whereas spray sheet thickness increases by 412.50% at a radial distance of 10 mm.
Conclusion: Bubble break-up is the main reason for the generation of perforations within an air-induction nozzle, leading to early break-up of the spray sheet and the production of large spray droplets. Bubble break-up can be effectively controlled by modifying the nozzle configuration.
Keywords: air-induction nozzle; bubble; nozzle configuration; perforation; spray sheet.
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