Fundamental motion characteristics and manipulation of ferromagnetic fluid droplet in a channel flow under external magnetic field

Ferromagnetic fluid can be used to as a carrier to transport other materials since its motion can be manipulated by external magnetic field and it is of great importance to reveal the motion regularity of ferromagnetic fluid droplets when they are used as carriers under the action of a magnetic field. In this work, numerical simulations and experimental visualizations were carried out to investigate the transportation process of a ferromagnetic fluid droplet and the controllable behavior of ferromagnetic fluid droplets under the action of a magnetic field. Based on the two-phase lattice Boltzmann method, the motion of ferromagnetic fluid droplets under magnetic field was simulated, and the shape evolution process of the droplets was revealed. Simulation results indicate that the changes of the droplet velocity and the mean outlet velocity of channel fluid all present fluctuation regularities due to the instability of droplet. It was also found that the transportation efficiency is weakened once the droplet contacts with the channel wall. For the ferromagnetic fluid droplet immersed in channel fluid, an external force generated by gradient magnetic field can be used to resist the gravity, and then, it will not sink to the lower channel wall, as revealed by the experiments, the droplet can move along the channel center.

Automated summary

Numerical simulations and experimental visualizations were conducted to investigate the transportation process and controllable behavior of ferromagnetic fluid droplets under the action of a magnetic field. The results showed that droplet velocity and shape evolution are influenced by droplet instability, and transportation efficiency decreases when the droplet contacts with the channel wall. However, the use of gradient magnetic field can help resist gravity and allow the droplet to move along the channel center.