The dynamics characteristics of droplet coalescence on fiber

Fiber coalescence is a simple and efficient technology for oil-water separation. In this work, based on chaos theory, the nonlinear dynamics chaotic characteristics of droplets on fiber under coalescence state was systematically investigated using the 0-1 detection method, and a coupling relationship model between chaotic characteristic value and coalescence frequency was established. Simultaneously, by employing image processing techniques, the evolution process of dynamic droplet coalescence on vertical fiber was explored, the influence of various factors on droplet coalescence characteristics were discussed, and the energy dissipation during droplet coalescence interactions was analyzed. The experimental results showed that under coalescence state, droplets motion on fiber exhibited chaotic characteristics, with a strong correlation between chaotic characteristic values and coalescence frequency (Person correlation coefficient was 0.979). Increasing fiber diameter and flow rate could significantly reduce the coalescence time of droplets, while the coalescence time of isooctane droplets was the shortest compared with other droplets. Additionally, the droplet coalescence process was accompanied by energy dissipation, and the energy dissipation increased with the decrease of diameter ratio. When the diameter ratio was 0.74, the maximum energy dissipation during droplet coalescence reached 3.391 x 10-6 J. Overall, these research findings not only deepen the understanding of droplet coalescence mechanisms on fiber surfaces but also provide an important reference for the design, optimization, and control of fiber coalescence equipment.