Atomization mechanisms and high-speed imaging of liquid sheet breakup in emulsion-based agricultural sprays: a review

The efficiency of pesticide application relies heavily on precise control of the factors influencing spray atomization, such as spray pressure, liquid physical properties, and the use of adjuvants. The breakup of liquid sheets plays a pivotal role in agricultural spray atomization, directly affecting droplet size distribution, deposition efficiency, and spray drift and environmental contamination. Emulsion-based sprays, widely used in agricultural applications, exhibit distinct breakup behaviors compared to water-based systems, especially in terms of liquid sheet destabilization and hole formation. This review systematically summarizes current theoretical models and experimental studies on the atomization mechanisms of emulsion liquid sheets, with a focus on hole-driven breakup dynamics and edge instabilities. Two primary rupture pathways—tearing rupture and puncture expansion are compared in terms of initiation conditions, expansion kinetics, and their implications for droplet formation. The influence of dispersed oil-phase components, Marangoni effects, and film viscoelasticity is analyzed to reveal their roles in destabilizing the liquid film. Advances in high-speed imaging technologies and image-based quantitative analysis methods are discussed, highlighting their value in visualizing transient film dynamics and validating atomization models. By integrating mechanistic insights with visual diagnostics, this review clarifies the physical underpinnings of emulsion atomization and identifies future research directions toward improved spray structure control and pesticide utilization.