Behaviors of droplet impacting on the single fiber with various cross-sectional shape

Droplet dispersion is extensively prevalent in industrial applications. However, the underlying mechanisms of droplet–fiber interactions, especially those involving fibers with novel cross-sectional shape (CSS), remain insufficiently understood. Therefore, the dispersion behaviors of droplets impacting a single fiber with varying CSS were investigated via computational fluid dynamics (CFD) simulation. First, the observations of droplet dynamics revealed that circular fiber (FC) split the droplet into two symmetrical parts, then converging and eventually mergeing into one before falling. The elliptical fiber (FE) promoted liquid re-aggregation into a single drop due to its streamlined shape. The quadrangular fiber (FQ) with sharp edges led to the formation of double fan-shaped films. Subsequently, the analysis of internal flow fields showed that fiber geometry affected velocity, pressure, and shear stress distributions, thereby determining liquid spreading and flow patterns. Furthermore, the liquid film thickness (h) profiles exhibited a “V” shape for FC and FE, whereas an “M” shape was found for FQ. Notably, FQ reduced h by an average of 35.4% compared to FC and showed a higher growth rate of liquid interfacial area (η), increasing by 25.6% on average relative to FC. Consequently, FQ exhibited superior cutting ability against liquids, facilitating droplet dispersion.