Динамика магнитных жидкостей, подвергающихся колебательному сдвигу

Abstract

The purpose of the work: to study the dynamics of the volume of a magnetic fluid levitating in an external magnetic field experiencing an oscillatory shift. Metods. The experiments were carried out on installations developed on the basis of known methods and equipment for magnetic measurements and manufactured independently. We study samples of magnetic fluid based on magnetite Fe3O4 stabilized with oleic acid. Kerosene was used as a carrier fluid. Results. Samples of a magnetic fluid with different physical parameters are considered, and the dependence of the viscosity on the magnetization of the magnetic field is investigated. The increase in viscosity in a magnetic field upon the action of a levitating MF column on the interface can be explained by an increase in particle interactions, which lead to MF microstructuring in the near-wall layer. The microstructure of the sample and the presence of large magnetic particles exert the greatest influence on the dynamics of a magnetic fluid, which undergoes an oscillatory shift and magnetoviscous effect. Conclusion. An assessment of the viscous magnetism effect in a thin near-wall layer of a column of magnetic fluid vibrating in a tube is made when a strong magnetic field is applied. The calculation of the viscosity value is carried out according to the formula obtained on the basis of two different theoretical approaches. The results of the work can be used to develop a method for express testing of magnetic fluid samples, as well as to develop acceleration and vibration sensors based on magnetic fluids. This method can be used to study magnetophoresis and aggregation of nanoparticles. Information on the viscous magnetic effect will be valuable for microfluidic technologies, where magnetic fluids with anisotropic particles, functionalized with various specific surfactants and flowing in microchannels, are used.