We treat the flow of ferrofluid in a cylindrical container subjected to a uniform rotating magnetic field, commonly referred to as spin-up flow. A review of theoretical and experimental results published since the phenomenon was first observed in 1967 shows that the experimental data from surface observations of tracer particles are inadequate for the assessment of bulk flow theories. We present direct measurements of the bulk flow by using the ultrasound velocity profile method, and torque measurements for water and kerosene based ferrofluids, showing the fluid corotating with the field in a rigid-body-like fashion throughout most of the bulk region of the container, except near the air-fluid interface, where it was observed to counter-rotate. We obtain an extension of the spin diffusion theory of Zaitsev and Shliomis, using the regular perturbation method. The solution is rigorously valid for ${\alpha }_K⪡\sqrt{3∕2}$ , where ${\alpha }_K$ is the Langevin parameter evaluated by using the applied field magnitude, and provides a means for obtaining successively higher contributions of the nonlinearity of the equilibrium magnetization response and the spin-magnetization coupling in the magnetization relaxation equation. Because of limitations in the sensitivity of our apparatus, experiments were carried out under conditions for which $\alpha \sim 1$ . Still, under such conditions the predictions of the analysis are in good qualitative agreement with the experimental observations. An estimate of the spin viscosity is obtained from comparison of flow measurements and theoretical results of the extrapolated wall velocity from the regular perturbation method. The estimated value lies in the range of ${10}^{-8}–{10}^{-12}\mathrm{kg}\mathrm{m}{\mathrm{s}}^{-1}$ and is several orders of magnitude higher than that obtained from dimensional analysis of a suspension of noninteracting particles in a Newtonian fluid.

Direct measurements of the bulk flow of a ferrofluid in a uniform rotating magnetic field were obtained using the ultrasonic velocity profile method. The fluid was observed to corotate with the field in a rigid-body-like fashion throughout the bulk of the container, except near the air-fluid interface, where it was observed to counterrotate. The results were found in qualitative agreement with the spin diffusion theory of Zaitsev and Shliomis [ J. Appl. Mech. Tech. Phys. 10, 696 (1969)].

An asymptotic solution is obtained for flow of a ferrofluid between two stationary coaxial cylinders of infinite extent, including the effects of spin viscosity. This solution takes into account the nonuniformity of the magnetic field in the annular space that arises as a consequence of the demagnetizing field of the inner cylinder. In the limit of zero spin viscosity the analysis predicts there is no flow in the annular gap. For nonzero spin viscosity the analysis predicts flow in the annulus with corotation of field and fluid close to the outer cylinder wall and counter-rotation close to the inner cylinder wall. The asymptotic predictions for the translational velocity are compared to experimental measurements obtained using the ultrasound velocity profile method for ferrofluid in an annular gap. The observed experimental velocity profiles are in qualitative agreement with the predictions of the asymptotic model, and transition between corotation to counter-rotation of fluid and field was observed at an intermediate radial position. These observations provide further evidence of the existence of couple stresses in ferrofluids and the importance of spin viscosity in describing some ferrofluid flows.

An essential understanding of the adsorptive phenomena involving nanomaterials and asphaltenes has received considerable attention in oil recovery and production applications. Particularly, iron oxide-based nanoparticles have emerged as advanced materials due to their unique physicochemical properties, including thermal conductivity and superparamagnetism. On this basis, the kinetics and adsorption isotherms of magnetite (Fe₃O₄) nanoparticles/asphaltene systems were investigated, as well as the synergistic effect of resins acting as stabilizing colloidal agents. The results indicated rapid asphaltene adsorption that, essentially, follows the phenomenological external mass transfer (EMT) model. At the equilibrium, the asphaltene adsorption was adequately described by the monolayer Langmuir model. By these findings, it was studied for the first time the effect of the adsorbed asphaltenes on the magnetic dipolar interactions in nanoparticles/asphaltene powder state configurations, by applying a simple analytical model based on magnetic susceptibility and demagnetizing field concepts. It was proven accurately that asphaltenes coated the surfaces of the nanoparticles forming layers that stimulate a steric repulsive barrier between particles and, thus, reducing the intensity of interactions. Accordingly, a theoretical method was validated to estimate the magnetic-size distribution parameters by comparison with the physical distribution data obtained by Transmission Electron Microscopy (TEM). Finally, from the magnetically modified dynamic rheological properties, it was inferred that isotropic aggregates are naturally formed in the absence of the magnetic field, and these morphological features were not dramatically changed after the imposition of the field, leading to direct extrapolation of the modeling-based procedure for powders to real colloidal configurations applied in oil field operations.