Theoretical analyses and experimental research on micro-nano composite magnetorheological grease for sealing liquids with different viscosities

Magnetorheological grease is a smart material that can be reversibly rheologically stimulated by an external magnetic field and has high suspension stability and high saturation magnetization. The preparation method of magnetorheological grease and the factors affecting the performance of magnetorheological grease sealing liquid were investigated in this study. To reduce the loss of adhesion of greases and improve the uniformity of magnetic particles during the preparation of magnetorheological grease, a method of magnetic permeation preparation was developed. The study utilizes a combination of finite element calculation and experimental analysis to investigate the pressure resistance of magnetorheological grease sealing liquids and the crucial influencing factors of the seal's temperature rise and friction torque. The effects of coolant temperature and flow rate on reducing temperature rise were investigated. The findings indicate that the pressure resistance of magnetorheological grease sealing liquid is affected by the saturation magnetization, viscosity, yield stress, density of the magnetorheological grease, as well as the molecular weight, density and viscosity of the sealed liquid. ●Developed magnetic penetration method to prepare magnetorheological grease to improve dispersion uniformity.●The viscosity of magnetorheological grease results from the combined effects of temperature, magnetic field, and shear rate.●The pressure resistance of magnetorheological grease sealing silicone oil is more excellent than that of sealing water.●The rise in temperature is related to the viscosity of magnetorheological grease and rotational speed.●Coolant temperature and flow rate impact on the sealing effect.