The effect of an external magnetic field on the breakup dynamics of a magnetic droplet in a micro-magneto fluidic system

Lab-on-chip technology is an emerging method that can handle volumes of droplets and fluids ranging from picoliters to microliters, offering fast analysis and low costs. Droplet generation and breakup within a microdevice are particularly useful for biomedical testing and synthesis. This study computationally investigates the impact of a magnetic field on the breakup of a magnetic droplet using OpenFOAM. The volume-of-fluid method tracks the interface of the second phase, and the magnetic force and force are implemented based on Maxwell's equations. The study examines how different intensities of magnetic field and the magnetic source position influence interface deformation, streamlines, breakup time, droplet generation frequency, and droplet size. The findings indicate that enhancing the magnetic power up to 0.18 T does not change the daughter droplets' size but reduces the breakup time by approximately 30 %. As the magnetic magnitude rises beyond 0.18 T up to 0.6 T, the size of the generated particles decreases, and the pressure drop in the microchannel increases after each breakup. In contrast, within the lower magnetic field range (0–0.18 T), there is no significant change in pressure or pressure drop during droplet movement and after breakup.