scholarly journals Study on MHD Cylindrical Couette Flow and Rheological Properties of Some Magnetic Suspensions

2019 ◽  
Vol 16 (1) ◽  
pp. 119-140
Author(s):  
S.E. E. Hamza
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Magnetic Force ◽  
Flow Direction ◽  
Practical Importance ◽  
Magnetic Field Effects ◽  
Shear Rates ◽  
Concentric Cylinders ◽  
Cylindrical Couette Flow ◽  
Water Glycerol

The study of magnetic suspensions (MS) and magnetic field effects on their rheological properties is of evident practical importance due to its ability to orient and change their physical properties, especially their viscosity, by magnetic fields. This research presents the effect of a uniform magnetic field on the flow of MS in the annular region between two concentric cylinders. The motion of the fluid is due to the rotation of the inner cylinder with a constant angular velocity. An exact solution of the governing equations is obtained in the form of modified Bessel functions of the first and second kinds. The torque, which must be applied to the inner cylinder in order to maintain the rotation, is also calculated. The results show that as the magnetic parameter increases, the velocity profile decreases, while the torque increases due to the effect of magnetic force against the flow direction. In order to model the magnetoviscous effects, experiments were performed for different shear rates and different magnetic field strengths by using specially designed rheometers. The studied samples are iron oxide-water-glycerol system,  ferrofluid nanoparticles, MAG DX biocompatible ferrofluid. The theoretical analysis is based on Giesekus model for MS. This model gives more accurate results and takes into account the effects of viscoelastic shear thinning characteristics. It is found that a magnetic field increases the viscosity of all suspensions under consideration. Finally, new proposed correlation for the viscosity of MS as a function of both shear rate and magnetic field has been suggested.

Evaluation of a Constitutive Equation for Magnetorheological Fluids in Shear and Elongational Flows

Aerospace ◽  
2005 ◽  
Author(s):  
Constantin Ciocanel ◽  
Glenn Lipscomb ◽  
Nagi G. Naganathan
Keyword(s):  
Magnetic Field ◽  
Constitutive Equation ◽  
Magnetic Force ◽  
Close Contact ◽  
Flow Direction ◽  
Particle Structure ◽  
Mr Fluids ◽  
Particle Pairs ◽  
Elongational Flows ◽  
Microstructural Model

A microstructural model of the motion of particle pairs in MR fluids is proposed that accounts for both hydrodynamic and magnetic field forces. A fluid constitutive equation is derived from the model that allows prediction of velocity and particle structure fields. Results for simple shear and elongational flows are presented for cases where particle pairs remain in close contact so they are hydrodynamically equivalent to an ellipsoid of aspect ratio two. Additionally, only the magnetic force component normal to the vector connecting the centers of a particle pair affects motion. Shear flow results indicate particle pairs rotate continuously with the flow at low magnetic fields while a steady state is reached at high fields. For elongational flows, when the applied magnetic field is parallel to the elongation direction, particle pairs orient in the field/flow direction. Either orientation is possible when the field is perpendicular to the flow.

scholarly journals Solidification of Immiscible Alloys under High Magnetic Field: A Review

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 525
Author(s):  
Chen Wei ◽  
Jun Wang ◽  
Yixuan He ◽  
Jinshan Li ◽  
Eric Beaugnon
Keyword(s):  
Magnetic Field ◽  
High Magnetic Field ◽  
Microstructure Evolution ◽  
Magnetic Force ◽  
Solidification Process ◽  
Solidification Microstructure ◽  
Migration Behavior ◽  
Magnetic Field Effects ◽  
Immiscible Alloys ◽  
Immiscible Alloy

Immiscible alloy is a kind of functional metal material with broad application prospects in industry and electronic fields, which has aroused extensive attention in recent decades. In the solidification process of metallic material processing, various attractive phenomena can be realized by applying a high magnetic field (HMF), including the nucleation and growth of alloys and microstructure evolution, etc. The selectivity provided by Lorentz force, thermoelectric magnetic force, and magnetic force or a combination of magnetic field effects can effectively control the solidification process of the melt. Recent advances in the understanding of the development of immiscible alloys in the solidification microstructure induced by HMF are reviewed. In this review, the immiscible alloy systems are introduced and inspected, with the main focus on the relationship between the migration behavior of the phase and evolution of the solidification microstructure under HMF. Special attention is paid to the mechanism of microstructure evolution caused by the magnetic field and its influence on performance. The ability of HMF to overcome microstructural heterogeneity in the solidification process provides freedom to design and modify new functional immiscible materials with desired physical properties. This review aims to offer an overview of the latest progress in HMF processing of immiscible alloys.

Effect of a magnetic field on the rheological properties of iron oxide–water–glycerol system

2016 ◽  
Vol 55 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Sergey A. Vshivkov ◽  
Elena V. Rusinova ◽  
Andrei G. Galyas
Keyword(s):  
Magnetic Field ◽  
Iron Oxide ◽  
Rheological Properties ◽  
Water Glycerol

Induced Magnetic Field Effects on Peristaltic Flow in a Curved Channel

2015 ◽  
Vol 70 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Saima Noreen
Keyword(s):  
Magnetic Field ◽  
Magnetic Force ◽  
Flow Analysis ◽  
Peristaltic Flow ◽  
Planar Channel ◽  
Magnetic Field Effects ◽  
Induced Magnetic Field ◽  
Curved Channel ◽  
Long Wavelength ◽  
Curvature Effects

AbstractThe peristaltic flow of an incompressible viscous fluid in a curved channel is investigated. The flow analysis is conducted in the presence of an induced magnetic field. A long-wavelength and low-Reynolds number approach is followed. The stream function, pressure gradient, magnetic force function, induced magnetic field, and current density are constructed. We observed that symmetry in the profiles of u and ϕ is disturbed because of curvature effects. For larger values of curvature k, results of planar channel are deduced. The effects of significant parameters have been portrayed and discussed.

MR Fluid Behavior Under Constant Shear Rates and High Magnetic Fields Over Long Time Periods

Aerospace ◽  
2004 ◽  
Author(s):  
Constantin Ciocanel ◽  
Kevin Molyet ◽  
Hideki Yamamoto ◽  
Sheila L. Vieira ◽  
Nagi G. Naganathan
Keyword(s):  
Magnetic Field ◽  
Shear Rate ◽  
Shear Strain ◽  
Rheological Properties ◽  
Smart Materials ◽  
Shear Stresses ◽  
Mr Fluid ◽  
Shear Rates ◽  
Constant Shear ◽  
Mechanical Devices

MR fluids are smart materials that reversibly change their rheological properties in the presence of a magnetic field. Their capability to support a high range of shear stresses makes them an ideal component of many mechanical devices. However, to be suitable for applications requiring a large number of cycles, e.g. a clutch, the long term behavior of these fluids needs to be thoroughly investigated and well understood. The paper presents a new MR cell design along with a study of the shear rate, shear strain, magnetic field and time influences on the properties and behavior of a MR fluid tested for long periods of time. The MR cell is required to adapt a commercially available rheometer to measure the rheological properties of the fluid. Overall characteristics of the designed MR cell output capability are provided. Constant shear rate tests, two hours in duration, have been performed at shear rates between 0.1 and 200 l/s under magnetic field intensities up to 0.4 T. The rheological measurements indicated that the time, the shear strain and the shear rate influence the fluid’s shear stress magnitude.

Oscillating Magnetic Field Effects on Convective Instability of Ferrofluids

2006 ◽  
Author(s):  
P. N. Kaloni
Keyword(s):  
Magnetic Field ◽  
Convective Instability ◽  
Magnetic Force ◽  
Convective Stability ◽  
Magnetic Field Effects ◽  
Periodic Magnetic Field ◽  
Force Modulation ◽  
Field Effects ◽  
Oscillating Magnetic Field ◽  
Time Periodic

Convective instability of a ferrofluid layer under gravity and a vertical time periodic magnetic field is investigated. Consideration, at the present, is given to quasistationary ferrohydrodynamic theory and influence of periodic magnetic force modulation on the convective stability is briefly discussed.

RHEOLOGICAL PROPERTIES OF NOVEL MAGNETORHEOLOGICAL FLUIDS

2007 ◽  
Vol 21 (28n29) ◽  
pp. 4849-4857 ◽  
Author(s):  
S. MANTRIPRAGADA ◽  
X. WANG ◽  
F. GORDANINEJAD ◽  
B. HU ◽  
A. FUCHS
Keyword(s):  
Magnetic Field ◽  
Rheological Properties ◽  
Yield Stress ◽  
Parallel Plate ◽  
Magnetorheological Fluids ◽  
High Yield ◽  
Iron Particles ◽  
Shear Rates ◽  
Low Viscosity ◽  
Mr Fluids

The rheological properties of novel MR fluids are characterized using a parallel plate MR shear rheometer. In these MR fluids the surface of iron particles is coated with a polymer. The rheological properties are measured and compared at various magnetic field strengths, shear rates and strain amplitudes. It has been shown that these MR fluids exhibit stable and desirable rheological properties such as, low viscosity and high yield stress.

Study of MFM Application in Semiconductor Failure Analysis

2004 ◽  
Author(s):  
Way-Jam Chen ◽  
Lily Shiau ◽  
Ming-Ching Huang ◽  
Chia-Hsing Chao
Keyword(s):  
Magnetic Field ◽  
Failure Analysis ◽  
Magnetic Force Microscopy ◽  
Magnetic Force ◽  
Current Flow ◽  
Force Microscopy ◽  
The Magnetic Field ◽  
A Current

Abstract In this study we have investigated the magnetic field associated with a current flowing in a circuit using Magnetic Force Microscopy (MFM). The technique is able to identify the magnetic field associated with a current flow and has potential for failure analysis.

scholarly journals Jet Impingement Heat Transfer of Confined Single and Double Jets with Non-Newtonian Power Law Nanofluid under the Inclined Magnetic Field Effects for a Partly Curved Heated Wall

2021 ◽  
Vol 13 (9) ◽  
pp. 5086
Author(s):  
Fatih Selimefendigil ◽  
Hakan F. Oztop ◽  
Ali J. Chamkha
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Particle Size ◽  
Aspect Ratio ◽  
Power Law ◽  
Volume Fraction ◽  
Inclined Magnetic Field ◽  
Magnetic Field Effects ◽  
Power Law Nanofluid ◽  
Power Law Index

Single and double impinging jets heat transfer of non-Newtonian power law nanofluid on a partly curved surface under the inclined magnetic field effects is analyzed with finite element method. The numerical work is performed for various values of Reynolds number (Re, between 100 and 300), Hartmann number (Ha, between 0 and 10), magnetic field inclination (γ, between 0 and 90), curved wall aspect ratio (AR, between 01. and 1.2), power law index (n, between 0.8 and 1.2), nanoparticle volume fraction (ϕ, between 0 and 0.04) and particle size in nm (dp, between 20 and 80). The amount of rise in average Nusselt (Nu) number with Re number depends upon the power law index while the discrepancy between the Newtonian fluid case becomes higher with higher values of power law indices. As compared to case with n = 1, discrepancy in the average Nu number are obtained as −38% and 71.5% for cases with n = 0.8 and n = 1.2. The magnetic field strength and inclination can be used to control the size and number or vortices. As magnetic field is imposed at the higher strength, the average Nu reduces by about 26.6% and 7.5% for single and double jets with n greater than 1 while it increases by about 4.78% and 12.58% with n less than 1. The inclination of magnetic field also plays an important role on the amount of enhancement in the average Nu number for different n values. The aspect ratio of the curved wall affects the flow field slightly while the average Nu variation becomes 5%. Average Nu number increases with higher solid particle volume fraction and with smaller particle size. At the highest particle size, it is increased by about 14%. There is 7% variation in the average Nu number when cases with lowest and highest particle size are compared. Finally, convective heat transfer performance modeling with four inputs and one output is successfully obtained by using Adaptive Neuro-Fuzzy Interface System (ANFIS) which provides fast and accurate prediction results.

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