Ferrohydrodynamic Research Articles

Combined fluid and ferrofluid buoyancy force, heat absorption and non linear ferro-viscosity effects on ferro- hydrodynamics fluid flow in orthogonal porous surface

Mixed convection incompressible ferro-hydrodynamic (FHD) boundary layer fluid flow on vertical porous curvilinear orthogonal surfaces is examined in our present study in presence of combined fluid and ferro-fluid buoyancy force, nonlinear ferro-viscosity parameter, and heat absorption/generation effects. Design/Methodology/Approach: Types of Prandtl momentum and thermal boundary layer partial differential equations in a curvilinear system are converted into non-dimensional ordinary nonlinear differential equations (ODE) by introducing dimensionless velocities, temperature functions and similarity variable. Missing initial conditions are found by shooting method and solving the system of nonlinear ODEs by Runge-Kutta integration scheme of order six. With the help of MATLAB, the numerical solutions are graphically displayed in the forms of primary velocity profile, secondary velocity profile, and temperature profile. Three types of magnetic nano-ferrofluid are considered such as water-based ferrofluid (Taiho W-40), Hydrocarbon based ferrofluid (EMG-901) and kerosene-based ferrofluid (C1-20B) whose Prandtl numbers are 44.3, 79.3 and 128 respectively shown in Table 1. For kerosene based ferro-fluid, Table 3 presents the coefficient of skin friction and heat flux. Finding: The effects of combined fluid and ferrofluid buoyancy forces, nonlinear ferro-viscosity parameter, suction/injection, and heat absorption/generation parameters on the velocity and temperature profiles are investigated. Our physical interest is to calculate the local shearing stresses and the local heat flux at the surface. Finally, we have made comparisons of the results which are highlighted the validity of our numerical calculations adopted for the presence study.

Numerical analysis of the behavior of two-phase blood flow in locally magnetized vessel

The main purpose of this study is to analyze the behavior of non-Newtonian blood flow under localized magnetic field. To that end, we consider a 2-dimensional and two-phase fully-developed biomagnetic fluid model in a rectangular artery. The blood flow model considers the ferrohydrodynamic (FHD) and magnetohydrodynamics (MHD) parameters, which differ from the traditional model based upon Navier-Stokes equations. An external user-defined (UDF) source code was used to define fully-developed flow, viscosity, FHD and MHD properties in magnetic and non-magnetic regions. The numerical outcomes are evaluated in consideration of their potential uses in the field of magneto-hemorheology. All the physical parameters used to interpret the findings are consistent with the pathological conditions. The solutions are displayed as velocity, stream function, temperature contours. The study reveals that blood flow can be regulated by modifying the magnetic field strength, artery diameter, and concentration of red blood cells within the artery. In particular, it could be useful for surgical treatments of cancer and dengue diseases in the extraction of affected red blood cells from the bloodstream.

Convective heat transfer enhancement and entropy generation analysis for radiative flow of ferrofluid inside the enclosure with non-uniform magnetic field

The present work consists of investigating the thermal performance and entropy generation for the non-isothermal radiative-convective flow of magnetic-ferrofluid inside the cavity exposed to the variable magnetic field. The effects of Lorentz and Kelvin forces for magnetized liquid are associated with magnetohydrodynamic (MHD) and ferrohydrodynamic (FHD) are examined during this study. The penalty method is used to eliminate pressure terms from governing nonlinear system of partial differential equations, and then Galerkin finite element is utilized to reduce the system into a system of algebraic equations, which is then solved with the help of Newton Raphson method to obtain the required (unique) solution. The obtained results show that the thermal mixing and entropy generation increases with an increase in the magnetic number Mnf. The concentration of ferroparticles volume fraction (ϕ) from 0 to 0.05 increases the heat transfer rate by 62.78% and decreases the total entropy generation by 57.3%. The maximum 93.62% augmentation in the heat exchange rate is obtained at ϕ=0.05 and Mnf=103. The results of the present work can be used in obtaining geometric parameters and optimizing designs for effective energy transfer in chemical reactors, solar collectors, nuclear magnetic resonance imaging, heat exchangers, and dye removal from textile wastewater.

Finite Element Analysis of Biomagnetic Fluid Flow in a Channel with an Overlapping Stenosis

Analysis of biomagnetic fluid (blood) flow (BFD) is important due to the potential biomedical applications that have been proposed such as cell separation for magnetic devices, drug delivery using magnetic particles for the treatment of cancer tumours, hyperthermia, and the reduction of bleeding during surgeries. In this study, the effects of spatially varying magnetic field on a straight channel with an overlapping stenosis is investigated numerically using finite element method (FEM). The mathematical model of biomagnetic fluid is constructed based on the coupled study of Navier-Stokes equations with the principles of ferrohydrodynamic (FHD). While the flow in a constricted artery is considered to be Newtonian, steady, two-dimensional and isothermal. Galerkin finite element method is used to discretize the governing equations and then the source code is developed by using MATLAB software. The source code is validated, and the results is compared with the previous literature. Based on the findings, the introduction of magnetic field alters the behaviour of blood flow in the area near the magnetic source. The increment of magnetic field intensity near stenosis area causes the recirculation area downstream to become smaller. This could be seen from the velocity profile and streamline pattern of constricted artery.

A lattice Boltzmann method for two-phase nanofluid under variable non-uniform magnetic fields

In this study, a new lattice Boltzmann scheme is developed for the two-phase CuO–H2O nanomagnetic fluid (ferrofluid) under a non-uniform variable magnetic field. It introduces the second-order external force term including both MHD (magnetohydrodynamic) and FHD (ferrohydrodynamic) into the lattice Boltzmann equation. The square cavity and a heat source inside the circular cavity with natural convections of nanofluid are investigated, respectively. The effects of Rayleigh number (Ra), the volume fraction of nanoparticles (φ), Hartmann number (Ha) generated by MHD, and magnetic number (MnF) generated by FHD on the nanofluid flow and heat transfer properties, as well as the total entropy generation (Stot) have been examined. The two-phase lattice Boltzmann model has demonstrated that it is more accurate in predicting the heat transfer of nanofluid than the single-phase model. Consequently, the results calculated by the single-phase and the two-phase methods show the opposite trends. It indicates that nanoparticles could enhance heat transfer with maximum values of 1.78% or deteriorate heat transfer with maximum values of 14.84%. The results of the circular cavity show that Ha could diminish the flow intensity, whereas MnF could enhance it. The average Nusselt number (Nuave) on the heat source decreases with the augments of Ha and MnF but increases with Ra. An optimal volume fraction φ = 1% for heat transfer is obtained except for Ra = 104. Stot achieves the maximum value at Ha = 40 when Ra = 105. It increases with a rise of Ra but reduces with an increment of φ.

BOUNDARY LAYER ANALYSIS FLOW PAST A POROUS ROTATING DISK WITH DUFOUR AND SORET EFFECTS

Analysis of a boundary layer flow past a porous rotating disk with Dufour and Soret effects are carried out mathematically with the formulated problem presented in its rectangular form. These problems correspond to the continuity, momentum, energy and concentration equations. The formulated equations (PDE) are contracted to a reduced nonlinear coupled equation (ODE) via some variables. The ODEs were solve using the decomposition method and the results obtained agreed with those in the literatures. The physical quantities that occur are presented and varied graphically on the fluid radial, tangential, axial velocity, temperature and concentration profiles. It seens that both ferro hydro dynamic (FHD) interactive parameter and rotational parameter enhances the radial, axial, temperature and concentration while they lead to decrease in tangential velocity of the fluid.

Magnetohydrodynamic and Ferrohydrodynamic Interactions on the Biomagnetic Flow and Heat Transfer Containing Magnetic Particles Along a Stretched Cylinder

In this paper, the laminar, incompressible and viscous flow of a biomagnetic fluid containing Fe33O44 magnetic particles, through a two dimensional stretched cylinder is numerically studied in the presence of a magnetic dipole. The extended formulation of Biomagnetic Fluid Dynamics (BFD) which involves the principles of MagnetoHydroDynamic (MHD) and FerroHydroDynamic (FHD) is adopted. The pressure terms are also taken consideration. The physical problem which is described by a coupled system of partial differential equations along with corresponding boundary conditions is converted to a coupled system of nonlinear ordinary differential equations subject to analogous boundary conditions utilizing similarity approach. The numerical solution is obtained by using an efficient technique which is based on a common finite difference method with central differencing, a tridigonal matrix manipulation and an iterative procedure. For verification proposes a comparison with previously published results is also made. The numerous results concerning the axial velocity, temperature, pressure, skin friction coefficient, rate of heat transfer and wall pressure parameter are presented for various values of the parameters. The axial velocity is decreased as the ferromagnetic number increases, temperature is enhanced with increasing values of the magnetic parameter.

Effect of Thermal Radiation on Biomagnetic Fluid Flow and Heat Transfer over an Unsteady Stretching Sheet

This study examines the influence of thermal radiation on biomagnetic fluid, namely blood that passes through a two-dimensional stretching sheet in the presence of magnetic dipole. This analysis is conducted to observe the behavior of blood flow for an unsteady case, which will help in developing new solutions to treat diseases and disorders related to human body. Our model is namely biomagnetic fluid dynamics (BFD), which is consistent with two principles: ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD), where blood is treated as electrically conductive. It is assumed that the implemented magnetic field is sufficiently strong to saturate the ferrofluid, and the variation of magnetization with temperature may be approximated with the aid of a function of temperature distinction. The governing partial differential equations (PDEs) converted into ordinary differential equations (ODEs) using similarity transformation and numerical results are thus obtained by using the bvp4c function technique in MATLAB software with considering applicable boundary conditions. With the help of graphs, we discuss the impact of various parameters, namely radiation parameter, unsteady parameter, permeability parameter, suction parameter, magnetic field parameter, ferromagnetic parameter, Prandtl number, velocity and thermal slip parameter on fluid (blood) flow and heat transfer in the boundary layer. The rate of heat transfer and skin friction coefficient is also computationally obtained for the requirement of this study. The fluid velocity decreases with increasing values of the magnetic parameter, ferromagnetic interaction parameter, radiation parameter whereas temperature profile increases for the unsteady parameter, Prandtl number, and permeability parameter. From the analysis, it is also observed that the skin friction coefficient decreases and the rate of heat transfer increases respectively with increasing values of the ferromagnetic interaction parameter. The most important part of the present analysis is that we neither neglect the magnetization nor electrical conductivity of the blood throughout this study. To make the results more feasible, they are compared with the data previously published in the literature and found to be in good accuracy.

Numerical study on mixed convective flow of water‐based magnetite nanofluid through a wavy channel containing porous blocks under the effect of an oscillating magnetic field

AbstractIn this paper, the convective flow of magnetite (Fe3O4)‐water nanofluid through a wavy channel containing porous blocks in the presence of a non‐uniform oscillating magnetic field with magnetohydrodynamic (MHD) and ferrohydrodynamic (FHD) effects is considered. This magnetic field is produced by two current‐carrying wires, which are placed at fixed positions on the outside of the channel. In the present study, we use a two‐phase model that considers the effects of thermophoresis and Brownian motion on the concentration of nanoparticles within the fluid. The associated system of partial differential equations is solved using the mixed finite element method with Taylor‐Hood elements and the effects of time t, Strouhal number , Hartmann number , magnetic number , solid volume fraction ϕ0, nanoparticle diameter on the fluid flow, heat transfer, concentration distribution and pressure drop within the channel are investigated.

Study of magnetic nanofluid flow in a square cavity under the magnetic field of a wire carrying the electric current in turbulence regime

In this paper, hydrodynamic and thermal behaviors of a magnetic nanofluid (H2O(l)-Fe3O4) in the turbulent regime (Ra > 106) are conducted. The velocity field is affected by the magnetic field of a wire carrying the electric current. The geometry of the problem is two-dimensional squares, that the left and right sides are at temperatures Th and Tc, respectively (Th>Tc). In addition, the upper and lower walls are insulated. The governing equations as continuity, momentum, and energy equation are formulated using the ferrohydrodynamic (FHD) principle for two-dimensional steady-state RANS with a turbulent V2-f model. Using the finite volume method and the SIMPLE algorithm, the model for y+<1 is discretized by coding in the C++ programming language. The single-phase simulation is performed for the range of Rayleigh(107≤Ra≤108), the volume fraction of 0⩽∅⩽0.03 with the diameter of the particles 6 nm, and the range of the magnetic numbers(0≤Mnf≤2.02×1012). The results show that the heat transfer rate increases with the increasing Rayleigh and magnetic numbers. And increasing the volume fraction of nanoparticles dependent on the magnetic number that leads to a change in the heat transfer rate.

Residence time distribution of passive scalars in magnetic nanofluid Poiseuille flow under uniform rotating magnetic fields

The diffusive and convective transport mechanisms that govern the residence time distribution (RTD) of magnetic nanofluid (ferrofluid) capillary Poiseuille flow under an external uniform rotating magnetic field (RMF) were experimentally and numerically investigated. The measured RTDs are reduced and approach plug flow under RMF excitation by shortening the elution time, stiffening the breakthrough rise, and delaying the breakthrough time as the RMF frequency and/or magnetic nanoparticle concentration increase(s). Ferrohydrodynamic (FHD) simulations predict the inception of secondary convective azimuthal flow but fail to explain the impact of the magnetic field on RTD evolution under the assumption of isotropic diffusion transport. The origin of anisotropy in scalar diffusive transport was elucidated by analyzing the rotational properties of magnetic nanoparticles with respect to ferrofluid vorticity and RMF arrangement. Therefore, independent measurement of an anisotropic effective diffusion tensor for RMF-excited quiescent ferrofluids facilitates improved FHD simulations of RTD without compromising the model’s predictive power.

Insight into the dynamics of ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD) nanofluids inside a hexagonal cavity in the presence of a non-uniform magnetic field

The ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD) are two important effects of a magnetic field in a liquid. FHD is the results of Kelvin force while MHD is the effect of a magnetic field due to Lorentz force. The present study aimed to evaluate the heat and mass transfer behavior of nanofluids inside a hexagonal enclosure in the presence of a non-uniform magnetic field considering the effects of Ferro-hydrodynamic (FHD) and Magneto-hydrodynamic (MHD). First, the concentration gradient of nanoparticles was captured due to the nanoscale forces. Then, the governing equations, including the continuity of nanofluid and nanoparticles, and momentum for vertical and horizontal direction were introduced, along with energy equation. Besides, the practical boundary condition of zero mass flux in nanoparticles at the walls was employed. Further, the governing equations were transformed into their non-dimensional form and solved numerically by the Finite Element Method (FEM). Furthermore, a systematic grid check was performed, and the results were compared with those of previous studies. Increasing magnetic number (Mnf) results in an increase in the heat and mass transfer rate. Increasing Lorentz force, in the form of Hartmann number (Ha) leads to a decrease in the rate of heat and mass transfer.

Ferro hydro dynamic analysis of heat transfer and biomagnetic fluid flow in channel under the effect of two inclined permanent magnets

Abstract Peripheral vascular diseases is one of the main causes of death in the world. It is disorders that cause the blood vessels to narrow, block, or spasm. Here, effects of two inclined rectangular permanent magnets field on heat transfer and flow characteristics of blood fluid in a channel, as a model of straight part of the aorta, has been investigated using FerroHydroDynamics (FHD) principles. Thermally and hydrodynamically fully developed flow is considered at the inlet of the vessel. Governing equations have been discretized using the finite volume method and the SIMPLE algorithm. Simulations have been carried out for different inclination angles of magnets and saturated magnetization. From the results, the magnetic field of two inclined magnets leads to increase heat transfer of blood fluid flow toward the walls. Moreover, major energy loss, arising from mean wall shear stress, is decreased but local or minor energy loss, arising from generated vortices, is increased. Furthermore, the formation of recirculation zones near the wall, where the magnetic drug can be trapped there for uptake to tissue, is observed.

Convective Boundary Layer Flow of Magnetic Nanofluids under the Influence of Geothermal Viscosity

The purpose of the present study is to examine the effects of geothermal viscosity on an unsteady flow of incompressible magnetic nanofluids (C1-20B &amp; Taiho-W40) due to a heated rotating disk. The modeled system of nonlinear coupled partial differential equations governing the unsteady flow together with the two point variable boundary conditions have been transformed into the set of non-linear coupled ordinary differential equations. The resultant set of equations is then solved by fourth order Runge-Kutta method in MATLAB using ODE45 with shooting technique for initial guess. The influences of geothermal viscosity variations ( for temperature &amp; for depth) along with the ferro-hydro-dynamic (FHD) interaction parameter and rotational parameter R on the flow and temperature field generated on the plate surface are elucidated. Besides the above profiles; effects of both, depth and temperature dependent viscosity parameters are also examined on the skin frictions, rate of heat transfer and boundary layer displacement thickness. The computed results for stronger (C1-20B) and weaker (Taiho-W40) convective magnetic nanofluids (MNF) have been discussed and compared vis-a-vis.

Modeling and analysis of biomagnetic blood Carreau fluid flow through a stenosis artery with magnetic heat transfer: A transient study.

We present a numerical investigation of tapered arteries that addresses the transient simulation of non-Newtonian bio-magnetic fluid dynamics (BFD) of blood through a stenosis artery in the presence of a transverse magnetic field. The current model is consistent with ferro-hydrodynamic (FHD) and magneto-hydrodynamic (MHD) principles. In the present work, blood in small arteries is analyzed using the Carreau-Yasuda model. The arterial wall is assumed to be fixed with cosine geometry for the stenosis. A parametric study was conducted to reveal the effects of the stenosis intensity and the Hartman number on a wide range of flow parameters, such as the flow velocity, temperature, and wall shear stress. Current findings are in a good agreement with recent findings in previous research studies. The results show that wall temperature control can keep the blood in its ideal blood temperature range (below 40°C) and that a severe pressure drop occurs for blockages of more than 60 percent. Additionally, with an increase in the Ha number, a velocity drop in the blood vessel is experienced.

Forced convection heat transfer in a semi annulus under the influence of a variable magnetic field

Since advective transport in a ferrofluid can be controlled by using an external magnetic field, magnetic nanofluid (ferrofluid) has various applications to heat transfer processes. Unlike free or forced convection, Ferrohydrodynamic convection is not yet well described. In the literature we see papers with constant magnetic fields; but the assumptions are not accurate, since the fields do not comply with the Maxwell’s equations of electromagnetism. In this study, forced convection heat transfer in a semi annulus lid under the influence of a variable magnetic field is studied. The enclosure is filled with ferrofluid (Fe3O4–water). Control Volume based Finite Element Method (CVFEM) is used to solve the governing equations considering both Ferrohydrodynamic (FHD) and Magnetohydrodynamic (MHD) effects. It is assumed that the magnetization of the fluid is varying linearly with temperature and magnetic field intensity. The effects Reynolds number, nanoparticle volume fraction parameter, magnetic number arising from FHD, and Hartmann number arising from MHD are analyzed. Obtained results indicate that the effects of Kelvin forces are more pronounced for high Reynolds number. Heat transfer enhancement has direct relationship with the Reynolds number and the magnetic number; while it has inverse relationship with the Hartmann number.

Magnetic particle capture for biomagnetic fluid flow in stenosed aortic bifurcation considering particle–fluid coupling

Magnetic nanoparticles drug carriers continue to attract considerable interest for drug targeting in the treatment of cancer and other pathological conditions. Guiding magnetic iron oxide nanoparticles with the help of an external magnetic field to its target is the basic principle behind the Magnetic Drug Targeting (MDT). It is essential to couple the ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD) principles when magnetic fields are applied to blood as a biomagnetic fluid. The present study is devoted to study on MDT technique by particle tracking in the presence of a non uniform magnetic field in a stenosed aortic bifurcation. The present numerical model of biomagnetic fluid dynamics (BFD) takes into accounts both magnetization and electrical conductivity of blood. The blood flow in the bifurcation is considered to be incompressible and Newtonian. An Eulerian–Lagrangian technique is adopted to resolve the hemodynamic flow and the motion of the magnetic particles in the flow using ANSYS FLUENT two way particle–fluid coupling. An implantable infinitely long cylindrical current carrying conductor is used to create the requisite magnetic field. Targeted transport of the magnetic particles in a partly occluded vessel differs distinctly from the same in a regular unblocked vessel. Results concerning the velocity and temperature field indicate that the presence of the magnetic field influences the flow field considerably and the disturbances increase as the magnetic field strength increases. The insert position is also varied to observe the variation in flow as well as temperature field. Parametric investigation is conducted and the influence of the particle size (dp), flow Reynolds number (Re) and external magnetic field strength (B0) on the “capture efficiency” (CE) is reported. The difference in CE is also studied for different particle loading condition. According to the results, the magnetic field increased the particle concentration in the target region. Analysis shows that there exists an optimum regime of operating parameters for which deposition of the drug carrying magnetic particles in a target zone on the partly occluded vessel wall can be maximized. The results provide useful design bases for in vitro set up for the investigation of MDT in stenosed blood vessels.

Simulation of Ferrofluid Flow for Magnetic Drug Targeting Using the Lattice Boltzmann Method

Abstract Influence of a spatially varying magnetic field on Fe3O4-plasma nanofluid flow in a vessel as a targeted drug delivery system is investigated. Combined effects of ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD) are considered in mathematic models. The lattice Boltzmann method is applied to solve the governing equations. Effects of active parameters, such as the Reynolds number and magnetic number on the flow characteristics, have been examined. Results indicate that the presence of the magnetic field affects considerably the flow field. Back flow occurs near the region where the magnetic source is located. Also, it can be found that the skin friction coefficient is a decreasing function of the Reynolds number and magnetic number.

Ferrofluid flow and heat transfer in a semi annulus enclosure in the presence of magnetic source considering thermal radiation

In this paper, ferrofluid flow and heat transfer in a semi annulus enclosure is investigated considering thermal radiation. The enclosure has a wall with constant heat flux boundary condition. Combined effects of Ferrohydrodynamic (FHD) and magnetohydrodynamic (MHD) are considered. It is assumed that the magnetization of the fluid is varying linearly with temperature and magnetic field intensity. Control Volume based Finite Element Method (CVFEM) is applied to solve the governing equations. The calculations were performed for different governing parameters namely; the Radiation parameter, Rayleigh number, nanoparticle volume fraction, Magnetic number arising from FHD and Hartmann number arising from MHD. Results show that Nusselt number is an increasing function of Rayleigh number, nanoparticle volume fraction, magnetic number while it is a decreasing function of with Hartmann number and radiation parameter.

Ferrohydrodynamic and magnetohydrodynamic effects on ferrofluid flow and convective heat transfer

In this paper, influence of an external magnetic field on ferrofluid flow and heat transfer in a semi annulus enclosure with sinusoidal hot wall is investigated. The governing equations which are derived by considering the both effects of FHD (Ferrohydrodynamic) and MHD (Magnetohydrodynamic) are solved via CVFEM (Control Volume based Finite Element Method). The effects of Rayleigh number, nanoparticle volume fraction, Magnetic number arising from FHD and Hartmann number arising from MHD on the flow and heat transfer characteristics have been examined. Results show that Nusselt number increases with augment of Rayleigh number and nanoparticle volume fraction but it decreases with increase of Hartmann number. Magnetic number has different effect on Nusselt number corresponding to Rayleigh number. Also it can be found that for low Rayleigh number, enhancement in heat transfer is an increasing function of Hartmann number and decreasing function of Magnetic number while opposite trend is observed for high Rayleigh number.