Experimental Investigation Of Magnetically Driven Flow Of Ferrofluids In Porous Media
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Experimental Investigation Of Magnetically Driven Flow Of Ferrofluids In Porous Media
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Author :
language : en
Publisher:
Release Date : 1998
Experimental Investigation Of Magnetically Driven Flow Of Ferrofluids In Porous Media written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with categories.
This report presents experimental results of the flow of ferrofluids in porous media to investigate the potential for precisely controlling fluid emplacement in porous media using magnetic fields. Ferrofluids are colloidal suspensions of magnetic particles stabilized in various carrier liquids. In the presence of an external magnetic field, the ferrofluid becomes magnetized as the particles align with the magnetic field. Potential applications of ferrofluids to subsurface contamination problems include magnetic guidance of reactants to contaminated target zones in the subsurface for in situ treatment or emplacement of containment barriers. Laboratory experiments of magnetically induced ferrofluid flow in porous media in this report demonstrate the potential for mobilizing ferrofluid and controlling fluid emplacement through control of the external magnetic field. The pressures measured in ferrofluid due to the attraction of ferrofluid to a permanent magnet agree well with calculated values. The results show that a predictable pressure gradient is produced in the fluid which is strong near the magnet and drops off quickly with distance. This pressure gradient drives the fluid through sand without significant loss of ferrofluid strength due to filtration or dilution. Flow visualization experiments of ferrofluid in water-filled horizontal Hele-Shaw cells demonstrate that ferrofluid obtains a consistent final arc-shaped configuration around the magnet regardless of initial configuration or flow path toward the magnet. Analogous experiments in actual porous media showed similar features and confirm the ability of ferrofluid to move through porous media by magnetic forces.
Experimental Study Of The Flow Of Ferrofluid In A Porous Media Under A Magnetic Field
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Author :
language : en
Publisher:
Release Date : 2016
Experimental Study Of The Flow Of Ferrofluid In A Porous Media Under A Magnetic Field written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Abstract : This research presents results from a laboratory-scale experimental setup that was designed to visualize the behavior of ferrofluid percolation through a porous media. Ferrofluids are colloidal suspensions made of magnetic particles of a few nanometers and stabilized in carrier liquids like water or mineral oil. Ferrofluids get magnetized and align themselves in the direction of a magnetic field when a field gradient is applied. With the help of this experiment we investigate the viability of controlling fluid flow in porous medium by a magnetic field in vicinity. The experiments show that ferrofluids can be used as a transporting media to push the higher viscosity fluid out of the porous media when magnetic forces are acting on it. The magnetic force produces stronger attractive forces on the ferrofluid around the magnet which results in a predictable arrangement which is in- dependent of the heterogeneity of the medium. When capillary or viscous forces are predominant during the 2-dimensional drainage of immiscible fluids in a permeable medium, the injected fluid forms very thin finger like structure which then retains the fluid being displaced in them. No fingers due to varying viscosities are observed during displacement by ferrofluids in the medium. Displacement visualization experiments in an oil saturated porous medium shows that ferrofluids obtain a rectangular shaped final configuration around the magnet, irrespective of the initial arrangement and flow path. The aim of this research is to control the instabilities that occur during the displacement of a fluid with the help of ferrofluid and magnetic field in vicinity. While the applications of ferrofluids are promising in the field of engineering, the results obtained are particularly relevant to the laboratory scale experiments where the weakening of magnetic strength due to increasing distance is a smaller limitation. Ferrofluids may find an immediate application in areas like enhancing oil recovery, in environmental engineering that requires maneuvering subsurface liquids in the field, treatment. Their properties could also be utilized in a situation that requires controlling the emplacement of fluid motion, guiding to or positioning to target zones in the subsurface without coming in direct access with it.
A Pore Scale Study Of Ferrofluid Driven Mobilization Of Oil
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Author : Fernando Saint-Martin de Abreu Soares
language : en
Publisher:
Release Date : 2015
A Pore Scale Study Of Ferrofluid Driven Mobilization Of Oil written by Fernando Saint-Martin de Abreu Soares and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.
Ferrofluids are stable dispersions of magnetic nanoparticles in a liquid carrier. The easily controllable magnetization of ferrofluids has motivated their use in a broad range of applications, from the non-intrusive imaging of organic tissues to the sealing and stability improvement of bearings. More recently, experiments verified the feasibility of injecting nanoparticles with specifically-designed coatings into permeable rocks without significant retentions or permeability loss. The possibility of controlling fluid displacements in a porous medium by manipulating magnetic stresses with an applied magnetic field suggests ferrofluids have a potential for subsurface applications, particularly in the field of enhanced oil recovery. Although extensive research has been devoted to the mechanics of ferrofluids, this topic is never analyzed under the conditions that are likely to occur in the subsurface environments. In particular, research on the behavior of two-phase systems in which the ferrofluid is wetting is still lacking. This work has the goal of simulating immiscible displacements influenced by the magnetic stresses acting on a wetting ferrofluid at pore scale. The simulations are based on a model for the quasi-static displacement of the liquid interface that couples the effects of the fluid flow with the magnetic stresses. An approach for the numerical simulation is developed based on a level set method for tracking the interface displacement, which is suitable for the complex shapes appearing in the pore space. The explicit-jump immersed interface method, which handles irregular domains with non-conforming grids, is employed in specific versions for the fluid flow and the magnetic field. The results indicate that the magnetic stress distribution is strongly affected by the configuration of the magnetic field in the regions of proximity between liquid interface and the solid surface. By applying a field parallel to the flow path, the magnetic stresses push the non-wetting phase away from the solid surfaces resulting in an interface configuration that reduces the flow viscous stresses and thus favors applications related to the transport of non-wetting liquids. A field perpendicular to the flow path generates magnetic stresses that contribute to the mobilization of ganglia trapped in snap-off geometries, suggesting ferrofluids can be used to reduce residual oil saturations in reservoirs in synergy with other methods.
Ferrofluid Spin Up Flows From Uniform And Non Uniform Rotating Magnetic Fields
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Author : Shahriar Rohinton Khushrushahi
language : en
Publisher:
Release Date : 2010
Ferrofluid Spin Up Flows From Uniform And Non Uniform Rotating Magnetic Fields written by Shahriar Rohinton Khushrushahi and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
When ferrofluid in a cylindrical container is subjected to a rotating azimuthally directed magnetic field, the fluid "spins up" into an almost rigid-body rotation where ferrofluid nanoparticles have both a linear and an angular "spin" velocity. Flow observations are often limited to the ferrofluid free surface due to the opaque nature of the ferrofluid and the surface flow can spin-up in the same or opposite directions to the direction of the rotating field. The mechanisms governing this flow have been attributed to surface driven flows that depend on the shape of the meniscus formed by the free surface. However, bulk flow experiments using ultrasound velocimetry show that even in the presence of a stationary cover, bulk ferrofluid flows would result when a rotating magnetic field was applied. The mechanisms explaining the bulk flows have been attributed by some authors to being a result of spin diffusion theory while others believe that non-uniform magnetic properties drive the flow, with both theories being rigorously explored in this thesis. This thesis applies ferrohydrodynamic analysis to extended fluid flow equations driven by magnetization forces and torques on the ferrofluid, Maxwell's equations relating magnetization, magnetic field and ferrofluid flow, and a Langevin magnetization relaxation constitutive law including the effects of fluid linear and spin velocities. Some key concepts investigated in this analysis are: (1) Ferrofluid filled cylindrical vessels of finite height placed within a uniform magnetic field result in non-uniform magnetic fields inside the ferrofluid due to demagnetization effects that can drive the flow; (2) A spherical vessel of ferrofluid in a uniform magnetic field has a resulting uniform magnetic field unless there is a spatial variation of magnetic properties, induced in this thesis by an external source of non-uniform magnetic field from a current carrying coil or a permanent magnet; and (3) COMSOL Multiphysics spin-diffusion modeling shows that spin viscosity can also initiate a flow due to spin-velocity boundary conditions which can hinder magnetic nanoparticle rotation near a wall or allow particles to roll along a wall due to flow vorticity. Ferrofluid spin-up flows were investigated that take into account demagnetizing effects associated with the shape of the container. The experiments conducted in this thesis involve using a sphere of ferrofluid in a uniform rotating field since a sphere has uniform and equal demagnetizing factors in all three Cartesian directions. The uniform rotating magnetic field is generated by two orthogonally placed spherical coils, known as "fluxballs" that generate a uniform magnetic field in the horizontal and vertical directions inside the fluxballs and a dipole field outside. By driving the coils with sinusoidal signals that are out of phase in time by 90 degrees a uniform rotating field is generated inside the test chamber containing the sphere of ferrofluid. The test sphere of ferrofluid is placed at the center of the larger surrounding "fluxball" machine. Negligible flows are measured within the ferrofluid filled sphere using ultrasound velocimetry in the "fluxball" machine with a uniform rotating magnetic field. COMSOL simulations using non-zero values of spin-viscosity, with a zero spin-velocity boundary condition at the outer wall, predict measurable flow while simulations setting spin-viscosity to zero result in negligible flow. Previously published values of spin-viscosity measured in cylindrical vessels are much larger than values allowed by kinetic theory because the flows, from which they were determined, are actually due to the demagnetizing field effects and not due to spin-diffusion. Experiments were also performed by partially filling the test sphere with ferrofluid but only 2/3 full, resulting in significant flows due to non-uniform magnetic fields from spatially dependent demagnetizing factors and possibly free surface effects. Ultrasound velocimetry measurements were also performed with a small permanent magnet or a DC/AC excited small coil on top of the ferrofluid filled test sphere, causing a nonuniform DC or AC magnetic field within the ferrofluid filled test sphere in addition to the uniform rotating magnetic field imposed by the fluxball coils. With an imposed non-uniform magnetic field component from magnet or coil, complex measurable flows with strong vortices are obtained. Formation of vortices is also confirmed in COMSOL simulations of an infinitely long cylinder subjected to a uniform rotating field and the field from an infinitely long permanent magnet. These measurements demonstrate that a non-uniform magnetic field or a non-uniform distribution of magnetic properties drive the flow. The spin-up ferrofluid flow in a rotating uniform externally applied field is highly dependent on the shape of the container due to demagnetizing effects. These demagnetizing effects in a finite-height ferrofluid filled cylindrical container create a non-uniform field inside the ferrofluid that drives the flow and is the cause for previously observed flows in the classic cylindrical spin-up flow experiments. COMSOL Multiphysics simulations applied to a cylinder of infinite height filled with ferrofluid show that spin-diffusion theory cannot be the dominant mechanism for spin-up flows as fitting the COMSOL analysis to measurements result in unphysically large values of spin viscosity. The unphysically large values of spin viscosity are obtained by attributing spin-up flow to be due to spin-diffusion alone rather than the correct non-uniform magnetic field effects. In conclusion, this thesis, through experimental results and numerical simulations, proves that non-uniform magnetic properties within the ferrofluid and not spin-diffusion theory is the driving mechanism for the measured flow.
Selected Problems In Fluid Flow And Heat Transfer
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Author : Artur J. Jaworski
language : en
Publisher: MDPI
Release Date : 2019-09-20
Selected Problems In Fluid Flow And Heat Transfer written by Artur J. Jaworski and has been published by MDPI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-09-20 with Technology & Engineering categories.
Fluid flow and heat transfer processes play an important role in many areas of science and engineering, from the planetary scale (e.g., influencing weather and climate) to the microscopic scales of enhancing heat transfer by the use of nanofluids; understood in the broadest possible sense, they also underpin the performance of many energy systems. This topical Special Issue of Energies is dedicated to the recent advances in this very broad field. This book will be of interest to readers not only in the fields of mechanical, aerospace, chemical, process and petroleum, energy, earth, civil ,and flow instrumentation engineering but, equally, biological and medical sciences, as well as physics and mathematics; that is, anywhere that “fluid flow and heat transfer” phenomena may play an important role or be a subject of worthy research pursuits.
Ferrofluids
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Author : Stefan Odenbach
language : en
Publisher: Springer
Release Date : 2008-01-11
Ferrofluids written by Stefan Odenbach and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-01-11 with Science categories.
Magnetic control of the properties and the flow of liquids is a challenging field for basic research and for applications. This book is meant to be both an introduction to, and a state-of-the-art review of, this topic. Written in the form of a set of lectures and tutorial reviews, the book addresses the synthesis and characterization of magnetic fluids, their hydrodynamical description and their rheological properties. The book closes with an account of magnetic drug targeting.
Multiphase Flow Behavior In Complex And Critical Environments
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Author : Zhiyuan Wang
language : en
Publisher: Frontiers Media SA
Release Date : 2022-12-29
Multiphase Flow Behavior In Complex And Critical Environments written by Zhiyuan Wang and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022-12-29 with Science categories.
Ferrofluid Flow Phenomena
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Author : Thomas Andrew Franklin
language : en
Publisher:
Release Date : 2003
Ferrofluid Flow Phenomena written by Thomas Andrew Franklin and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.
An Experimental Investigation Of The Thermomechanics Of Pipe Flow Of Magnetic Fluids In Response To Heating And Applied Magnetic Fields
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Author : Hooshyar M. Hamedani
language : en
Publisher:
Release Date : 1988
An Experimental Investigation Of The Thermomechanics Of Pipe Flow Of Magnetic Fluids In Response To Heating And Applied Magnetic Fields written by Hooshyar M. Hamedani and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1988 with Magnetic fluids categories.
An experimental investigation was carried out to determine the thermodynamics and fluid mechanics of the pipe flow of magnetic fluids. A water-based magnetic fluid was synthesized in the laboratory and its relative viscosity and magnetic properties were determined as a function of temperature. A "thermomagnetic pump" was built and tested in which temperature differences caused the magnetic fluid to circulate through a loop when subjected to a magnetic field. In a conceptual study, the pumping capabilities of such a flow circulation were considered for a thermal rejection system application. Pumping capabilities were observed to be directly related to the slope of the pyromagnetic curve. The sensitivity of the fluid was enhanced by the addition of zinc, manganese, and cobalt compounds. Fluid properties and flow parameters, including viscosity, magnetization, velocity, pressure, and temperature, were determined. A theoretical analysis was conducted for the prediction of values and analysis of the nature of the magnetic body forces induced in a magnetic fluid in the presence of heat and magnetic fields. A technique is introduced for the prediction of the maximum pressure difference that a "thermomagnetic pump" could produce. The advantages of a thermomagnetic pump are that it is noise free and reliable due to the absence of moving parts and control devices. At present, however, the flow rates generated by such a system are small and much research and development is needed for practical applications.
Magnetic Fluids
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Author : Elmars Blums
language : en
Publisher: Walter de Gruyter
Release Date : 2010-10-13
Magnetic Fluids written by Elmars Blums and has been published by Walter de Gruyter this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-10-13 with Science categories.