Behavior of disperse media based on magnetic fluids in inhomogeneous magnetic fields

Purpose. To study the behavior of dispersed media based on nanodispersed magnetic fluids: non-magnetic liquid and gaseous inclusions in a magnetic fluid, drops of magnetic fluid in a non-magnetic medium, as well as non-magnetic bubbles and drops covered with a shell of magnetic fluid in non-uniform magnetic fields.
Methods. The results were obtained experimentally using generally accepted methods and approaches. The setups used for the studies were developed independently, and data were collected using standard measuring equipment. The magnetic field induction value was measured using a TPU-01 teslameter with a Hall transducer connected to it. The magnetic field topology was modeled using the FEMM software embedded in the MathLab interactive environment. The platform not only models the magnetic field, but also qualitatively transforms the calculation results and visualizes them. The images of non-magnetic inclusions were processed in a specially developed program in the NI Labview system. Theoretical processing of the experimental results was based on known expressions of condensed matter physics, magnetic and classical hydrodynamics.
Results. Experimental dependences of the coordinate, velocity, size of dispersed media based on magnetic fluid on the magnetic field parameters, physical properties of magnetic and non-magnetic fluids are obtained. Based on the results of computer modeling in the FEMM program, an assessment of the forces acting on a non-magnetic drop and bubble in a magnetic fluid is carried out. The obtained experimental and theoretical data are consistent with each other.Experimental dependences of the position, velocity, and size of magnetic fluid-based disperse media on magnetic field parameters and the physical properties of magnetic and non-magnetic liquids were obtained. Computer simulations were used to estimate the forces acting on non-magnetic droplets and bubbles in a magnetic fluid. The experimental and theoretical data are in good agreement.
Conclusion. An inhomogeneous magnetic field allows for the control of the dynamics and behavior of magnetic fluidbased disperse media, paving the way for the development of controllable dispensers and systems for synthesizing active droplets.

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