Numerical simulation of contact and separation of magnetic particles under uniform magnetic field

Abstract

Under the action of an external magnetic field, the magnetic particles will be arranged along the direction of the magnetic field. The laws of physics that control these processes are well described in the literature. However, when the magnetic particles move in the fluid, the magnetic particles with different initial distances have different mutual influences, so there will be different laws of motion. Therefore, based on the motion theory of magnetic particles in Stokes fluid, this article discusses the motion law of the contact and separation of two circular magnetic particles in Newtonian fluid. First, we conduct theoretical and simulation modeling of two magnetic particles under the action of a uniform magnetic field, and verify the correctness of the simulation through experiments; secondly, we use numerical simulation to study the angle of repulsion and attraction of magnetic particles at different initial distances, and analyze at the same time the changes in the trajectory, speed, torque and force of magnetic particles in the process of motion are studied. Finally, the influence of external field conditions on the phenomenon of contact and separation of magnetic particles is studied. The study found that even when the initial angle between the magnetic particles is 90° with the direction of the magnetic field, the magnetic particles with different initial distances will repel under the action of repulsive force and then contact again and keep repelling these two states, a better explanation the reason for the agglomeration of magnetic particles at close range is explained.

Numerical simulation of effectively driving the trajectory of magnetic particles in a Newtonian fluid using a uniform magnetic field

“…The correctness of the simulation model has been fully verified in our previous study [34]. To verify the simulation result that magnetic particles in free contact will not be separated under the action of a vertical magnetic field, the magnetic particles are observed under a uniform magnetic field and their motion trajectories are captured.…”

“…As shown in figures 3(a) and (b), the separation distance and contact force are both zero. From t = 0 to 0.0044 s, the separation distance between the magnetic particles steadily increases, the magnetic particles move within the repulsion angle, and the offset motion occurs while repelling [34]. From t = 0.0044 to 0.0058 s, the separation distance between the magnetic particles decreases, which is because at t = 0.0044 s, the magnetic particles move with offset to the critical angle of attraction and repulsion.…”

“…And when the angle between the center line of magnetic particle and x-axis is −α, the magnetic particle Γ 1 moves upward and Γ 2 moves downward. The sizes of the exclusion and attraction domains have been fully explained in our previous publications [34].…”

“…When the angle between the magnetic particles is 90 • with the magnetic field direction, the magnetic particles will be separated by repulsion, and the direction of repulsion is perpendicular to the magnetic field direction. This work has been extensively studied by previous authors and was found in the content of our previous studies: Magnetic particles with different initial distances will have different angles of attraction and repulsion, and when the initial angle of magnetic particles and the magnetic field direction is 90 • magnetic particles in the process of repulsion will undergo different degrees of offset motion [34]. When the initial angle of magnetic particles is 0 • , 30 • , magnetic particles in the angle of attraction, magnetic particles directly attract contact into a chain.…”

Aglomeravimo procesais paremtų dujų srauto valymo technologijų taikymas ir palyginimas

“…Taip pat aglomeracijos efektyvumas kyla, kai didėja bendra masės koncentracija ir dalelių buvimo laikas aglomeratoriuje (Hautanen et al, 2010). Stebint skirtingų dydžių kietąsias daleles buvo nustatyta, kad neturinčios krūvio kietosios dalelės lengvai paslysta per didesnes daleles; kai dalelėms yra suteikiamas skirtingo poliariškumo krūvis, jų susidūrimo tikimybė stipriai išauga (Xu et al, 2021).…”