Simulation Analysis of the Motion of Superparamagnetic Particles in Liquid-Phase Fluid under a Magnetic Field

Abstract

Featured Application: Magnetic nanoparticles can be used in a wide range of applications with the aid of an external magnetic field, such as the recycling of magnetic adsorbents, the targeted delivery of drugs, and the targeted migration of lubricant particles. If the motion of magnetic particles in fluids under the influence of magnetic fields can be accurately calculated, this will help to increase the efficiency of particle utilization and broaden particles’ application areas. The present calculation starts with a model of the magnetization of magnetic particles in a magnetic field, and proposes a magnetization model for calculating magnetic forces based on the real magnetic property curves of magnetic particles. Some factors affecting the trajectory of this were further analyzed. Our calculations may serve as an important guide for targeted medicine in the biomedical field and the targeted lubrication of magnetically lubricated particles. Based on the magnetic response of magnetic particles, the targeting of particles to a target area under the modulation of an external magnetic field has been used in many applications. An accurate kinematic model is helpful to achieve accurate targeting of magnetic particles and to investigate the factors influencing the motion of the particles. In the present paper, a segmental magnetization model was proposed based on the real magnetization process of superparamagnetic particles to calculate the magnetic force, and this was compared with a traditional magnetization model. The effects of magnetic field strength and particle diameter on the trajectory of magnetic particles in fluids under a magnetic field were further analyzed using a finite element analysis software. The simulation results show that changing the particle size only affected the velocity of the particles and did not affect the trajectory. When magnetic field strength changed, magnetic particles showed different trajectories. Notably, when the magnetic field force in the Y direction was too large, meaning the gravity could be neglected, the trajectory of the particles no longer changed when the magnetic field strength was varied.