A multi-particle sedimentation stability investigation of magnetorheological fluid using the DEM

The settling stability of magnetorheological fluid (MRF) is an important aspect of magnetorheological research and an important indicator of MRF quality. The discrete element method (DEM) was proposed to study the multi-particle settling process of particles dispersed in silicon oil with different iron powder content, particle size, base viscosity, and added magnetic field. Then by preparing MRF, the zero-field viscosity, dynamic magnetic field viscosity, and settling stability of various MRF were measured and analyzed. The results show that the average kinetic energy of MRF settling decreases as particle content, particle size, and base fluid viscosity increase. With 50% iron powder content, 300 nm particle size, and 5% bentonite additive, MRF has the highest viscosity under zero field; under a dynamic magnetic field, the larger the particle size, the larger the viscosity; the MRF settling rate decreases by 18% with a change in iron powder content, decreases by 22.5% with a change in particle size to 300 nm, and decreases by 22% with a change in bentonite content. Under the application of a magnetic field, MRF hardly settles. The final experimental and simulation results are comparable, indicating that the MRF settlement characteristics can be predicted to some extent with the help of DEM simulation.