Hydrodynamics and morphologies of droplets coalescence on fiber

Abstract Fiber coalescence is an effective oil–water separation technology. In this article, the micro‐coalescence process of droplets on fiber was studied through high‐speed camera technology, and the hydrodynamics and morphology evolution in the process of droplet‐fiber coalescence were explored and compared with non‐fiber system. The results show that the change of the droplet surface morphology is local at the initial stage of the coalescence process. The droplet morphology changes obviously near the neck. The growth rate of the liquid bridge and the propagation speed of capillary wave in droplet‐fiber system are higher than those in non‐fiber system. At 0.8 ms, the capillary waves' polar angle difference between the two conditions reaches 10.44°. There is an obvious periodicity and damping attenuation mechanism in the oscillation process. In the droplet‐fiber system, the oscillation process attenuates faster and the average oscillation period is shorter. The droplet relaxes to a stable state more quickly.