Influence Of Magnetic Parameters Research Articles

Energy transport analysis in natural convective flow of water:Ethylene glycol (50:50)-based nanofluid around a spinning down-pointing vertical cone

The influence of the magnetic field on H2O−C2H6O2 (50:50)-based nanofluid over a heated and spinning vertical cone is deliberated. Water: ethylene glycol (50:50) mixture-based nanofluid with Al2O3 and Fe3O4 as nanoparticles exhibits higher thermal conductivity enhancement. Heat transfer analysis for the spinning vertical cone with a prescribed surface temperature was investigated. The influence of magnetic parameter, spin parameter, and nanoparticle volume fraction on tangential velocity profile, spin velocity profile, and thermal profile is analyzed. The results accord strongly with the findings of previous research works in the special cases. Computation shows that as magnetic parameter increases, the thicknesses of hydrodynamic and thermal boundary layers decrease and increase, respectively. The addition of nanoparticles (Al2O3 and Fe3O4) effectively enhances the skin friction coefficient and Nusselt number.

Investigation of heat and mass transfer for an MHD hybrid nanofluid flow over a rotating disk: a numerical investigation with supervised neural network

The key intention behind this research work is to investigate the heat and mass transfer phenomenon in the flow of hybrid nanofluid over a revolving disk with magnetohydrodynamic effects under consideration (MHD-HNRD). The flow model of the problem has been formulated in the form of PDEs which are further transmuted into ODEs with proper transforming equations. The influence of Magnetic parameter, Brinkman number, Prandtl number, Rotation parameter, and Concentration of the nanoparticles on velocities and thermal profile has been studied and reference data sets for the MHD-HNRD model are computed with the help of the renowned Lobatto-IIIA solver by varying these parameters. This reference solution is then subjected under the proposed solution methodology based on Levenberg–Marquardt Supervised Neural Networks (LMSNNs). An increase in heat transfer rate has been observed with the larger magnetic force and rotation rate. Graphical and numerical results based on mean-square errors (MSEs), time series response, error distribution plots, and regression plots endorse the precision, validity, and consistency of the proposed solution methodology. MSEs up to the level of 10–12 and performance learning curves predict the smoothness of the curves with the number of epochs confirming the accuracy, convergence, and validity of the designed solver.

Influence of heat transfer on MHD Carreau fluid flow due to motile cilia in a channel

Mucus transport mediated by motile cilia in the airway is an important defense mechanism for prevention of respiratory infections. Cilia motility can be affected by temperature difference and magnetic field. In this research, we investigate the combined effects of magnetic field and buoyancy force due to temperature difference. In the present study, mixed convective flow of a Carreau fluid model through a ciliated channel is modeled and analyzed by a symplectic metachoronal wave. The momentum and energy equations for the Carreau fluid are modeled and simplified by the stream function and small Reynold’s number approximation. The influence of magnetic parameter, Carreau fluid parameter, Brinkmann number and Weissenberg number on velocity, temperature and pressure gradient are presented via graphs. It is observed that Hartmann number helps to decelerate the flow, whereas Weissenberg number, Grashof number and Carreau fluid parameter are responsible for the accelerated flow. The heat transfer rate rises by increasing the values of Hartmann number, Weissenberg number, Carreau fluid parameter and Brinkmann number.

Non-similar radiative bioconvection nanofluid flow under oblique magnetic field with entropy generation

Motivated by exploring the near-wall transport phenomena involved in bioconvection fuel cells combined with electrically conducting nanofluids, in the present article, a detailed analytical treatment using homotopy analysis method (HAM) is presented of non-similar bioconvection flow of a nanofluid under the influence of magnetic field (Lorentz force) and gyrotactic microorganisms. The flow is induced by a stretching sheet under the action of an oblique magnetic field. In addition, nonlinear radiation effects are considered which are representative of solar flux in green fuel cells. A second thermodynamic law analysis has also been carried out for the present study to examine entropy generation (irreversibility) minimization. The influence of magnetic parameter, radiation parameter and bioconvection Rayleigh number on skin friction coefficient, Nusselt number, micro-organism flux and entropy generation number (EGN) is visualized graphically with detailed interpretation. Validation of the HAM solutions with published results is also included for the non-magnetic case in the absence of bioconvection and nanofluid effects. The computations show that the flow is decelerated with increasing magnetic body force parameter and bioconvection Rayleigh number whereas it is accelerated with stronger radiation parameter. EGN is boosted with increasing Reynolds number, radiation parameter and Prandtl number whereas it is reduced with increasing inclination of magnetic field.

Hydromagnetic forced convective flow of Carreau nanofluid over a wedge/plate/stagnation of the plate

The present work deals with the numerical study of two-dimensional incompressible, magnetohydrodynamic Falkner-Skan flow of Carreau nanofluid over wedge, plate and stagnation of the flat plate with convective boundary condition and chemical reaction. The influence of thermophoresis and Brownian motion are taken into account. Similarity transformations are utilized to transform the governing equations into a system of non-linear ordinary differential equations and solved numerically using Runge–Kutta Fehlberg scheme. A comparison has been made with the published results which reveals a good agreement. The influence of different physical parameters on flow, temperature and nanoparticle concentration distributions have been discussed in detail. A constitutional analysis has been made for skin friction coefficient, heat and mass transfer rates. Results elucidate that the influence of magnetic parameter on velocity is high over flat plate compared with wedge and stagnation point of the flat plate. Heat transfer performance is higher on shear thinning fluid compared with shear thickening fluid. Further, an increase in Brownian motion decreases the heat transfer rate but enhances the mass transfer rate.

Unsteady Free Convection Flow of Casson Nanofluid Over a Nonlinear Stretching Sheet

In this work, the buoyancy-driven unsteady flow of Casson nanofluid is analyzed. The effects of Brownian motion and thermophoresis on the flow fields are studied in the presence of magnetic field. Moreover, the convective boundary conditions on temperature and concentration walls are also considered. The similarity solutions are obtained numerically through Keller-box scheme. The accuracy of numerical results is verified via comparison with the results of accessible literature. Investigations perceived that the dimensionless temperature is not much affected with Brownian motion and thermophoretic parameters, whereas the impact of both parameters is noted stronger on nanoparticles concentration. The velocity field is observed more pronounced with the strength of magnetic parameter. Also, the influence of Casson fluid parameter on velocity and nanoparticle concentration is noticed opposite. The influence of magnetic parameter on velocity and temperature is seen more pronounced as compared to nanoparticle concentration. Further, the impact of Biot number on dimensionless temperature and nanoparticles concentration is found identical for both steady and unsteady flows. A reduction in velocity field is also observed with increment in slip parameter.

Brownian diffusion and thermophoresis mechanisms in Casson fluid over a moving wedge

Abstract The effect of Brownian diffusion and thermophoresis on electrically conducting mixed convection flow of Casson fluid induced by moving wedge is investigated in this paper. It is assumed that the wedge is saturated in a porous medium and experiences the thermal radiation and chemical reaction effects. The transformed nonlinear governing equations are solved numerically by Keller box scheme. Findings reveal that increase in Casson and magnetic parameters reduced the boundary layer thickness. The effect of Brownian motion and thermophoresis parameters are more pronounced on temperature profile as compared to nanoparticles concentration. The presence of thermal radiation assisted the heat transfer rate significantly. The influence of magnetic parameter is observed less significant on temperature and nanoparticles concentration.

Adomian decomposition method for Hall and ion-slip effects on mixed convection flow of a chemically reacting Newtonian fluid between parallel plates with heat generation/absorption

This paper analyzes the heat and mass transfer characteristics on mixed convective fully developed flow in an electrically conducting Newtonian fluid between vertical parallel plates. The chemical reaction, heat generation, Hall and ion-slip effects are taken into consideration. By using similarity transformations the nonlinear governing equations are reduced into dimensionless form and hence solved using Adomian decomposition method (ADM). The influence of magnetic parameter, Hall parameter, ion-slip parameter, chemical reaction parameter, and heat generation/absorption parameter on non-dimensional velocities, temperature and concentration profiles are exhibited graphically. In addition, the numerical data for skin friction, heat and mass transfer rates are shown in tabular form.

Thermomagnetic Convection in Porous Media: Effect of Anisotropy and Local Thermal Nonequilibrium

The onset of thermomagnetic convection in an anisotropic layer of Darcy porous medium in the presence of a uniform vertical magnetic field is investigated using a local thermal nonequilibrium (LTNE) model for energy equation representing the solid and fluid phases separately. Anisotropies in permeability as well as in fluid and solid thermal conductivities are considered. The principle of exchange of stability is shown to be valid. Asymptotic solutions for the Rayleigh number for both small and large values of scaled interphase heat transfer coefficient are presented and the comparison of results with those computed numerically shows good agreement. The mechanical and thermal anisotropy parameters have opposing influence on the stability characteristics of the system. Besides, the influence of magnetic parameters on the instability of the system is also reported.

MHD Flow with Hall current and Joule Heating Effects over an Exponentially Stretching Sheet

AbstractThe aim of the present paper is to study the influence of Hall current and Joule heating on flow, heat and mass transfer over an exponentially stretching sheet in a viscous fluid. Using similarity transformations the governing nonlinear coupled equations are converted into ordinary differential equations. These equations are linearized using the successive linearization method and then solved using the Chebyshev pseudo spectral method. The influence of magnetic parameter, Hall parameter, suction/injection parameter and slip parameter on the physical quantities are presented graphically. The obtained results are compared with the previously published results for special cases.

Numerical study of effect of induced magnetic field on transient natural convection over a vertical cone

In the present paper, an analysis has been performed to study the influence of induced magnetic field on the transient free convective flow of an electrically conducting and viscous incompressible fluid over a vertical cone. The coupled nonlinear partial differential equations governing the transient flow have been solved numerically by using the implicit finite difference method of Crank–Nicolson type. The influence of magnetic parameter, magnetic Prandtl number and semi-vertical angle of the cone on the velocity and induced magnetic field profiles has been illustrated graphically. Also, the local as well as average skin-friction and Nusselt number has been presented graphically. For result validation, we have done a comparative study and the present results are found to be in very good agreement with available results.

Magnetic properties of the magnetic hybrid membranes based on various polymer matrices and inorganic fillers

Magnetic hybrid membranes based on ethylcellulose (EC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and various magnetic praseodymium and neodymium powder microparticles as fillers were obtained. Permeability, diffusion and sorption coefficients of O2, N2 and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on constant pressure permeation technique. The microstructure studies and the phase analysis of magnetic membranes were also performed using SEM and XRD. The influence of magnetic parameters, like coercivity, remanence and saturation magnetization of created membranes on the gas transport properties was studied. The results showed that their coercivity depended on composition and microstructure of the magnetic powder. On the other hand, remanence and saturation magnetization increased with the increase of the powder addition in the membrane. It was found that the magnetic membrane's gas transport properties were improved with the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The decrease in powder particle size and associated increase of the membrane's coercivity also positively influenced the gas transport and separation properties of investigated membranes. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes had higher gas permeability, while their permselectivity and solubility coefficient values were rather maintained or slightly increased. The results also showed that the magnetic powder content enhanced significantly gas diffusivity in EC and PPO membranes. It was also analyzed the dependence of the drift coefficient w on the magnetic parameters of investigated membranes. The correlation between the membrane selectivity, permeability and magnetic properties with their XRD characteristics was stated.

Effect of rotation on ferromagnetic porous convection with a thermal non-equilibrium model

The effect of rotation on the onset of thermal convection in a horizontal layer of ferrofluid saturated Brinkman porous medium is investigated in the presence of a uniform vertical magnetic field using a local thermal non-equilibrium (LTNE) model. A two-field model for temperature representing the solid and fluid phases separately is used for energy equation. The condition for the occurrence of stationary and oscillatory convection is obtained analytically. The stability of the system has been analyzed when the magnetic and buoyancy forces are acting together as well as in isolation and the similarities as well as differences between the two are highlighted. In contrast to the non-rotating case, it is shown that decrease in the Darcy number Da and an increase in the ratio of effective viscosity to fluid viscosity Λ is to hasten the onset of stationary convection at high rotation rates and a coupling between these two parameters is identified in destabilizing the system. Asymptotic solutions for both small and large values of scaled interphase heat transfer coefficient H t are presented and compared with those computed numerically. Besides, the influence of magnetic parameters and also parameters representing LTNE on the stability of the system is discussed and the veracity of LTNE model over the LTE model is also analyzed.

Unsteady MHD free convective flow past a semi-infinite vertical wall with induced magnetic field

In this paper, the effect of an induced magnetic field on unsteady hydromagnetic free convective flow of an electrically conducting fluid past a semi-infinite vertical plate is considered. The coupled non-linear partial differential equations in non-dimensional form have been solved by implicit finite difference method of Crank–Nicolson type. The influence of magnetic parameter and magnetic Prandtl number on the velocity, temperature and induced magnetic field at a fixed cross-section, as well as on the skin-friction and Nusselt number on the heated surface, have been shown graphically. It is found that the effect of magnetic parameter is to decrease the velocity, temperature and induced magnetic fields while the effect of magnetic Prandtl number is to increase them.

Effect of Thermal Non-Equilibrium on Convective Instability in a Ferromagnetic Fluid-Saturated Porous Medium

The effect of local thermal non-equilibrium (LTNE) on the onset of thermomagnetic convection in a ferromagnetic fluid-saturated horizontal porous layer in the presence of a uniform vertical magnetic field is investigated. A modified Forchheimer-extended Darcy equation is employed to describe the flow in the porous medium, and a two-field model is used for temperature representing the solid and fluid phases separately. It is found that both the critical Darcy–Rayleigh number and the corresponding wave number are modified by the LTNE effects. Asymptotic solutions for both small and large values of scaled interphase heat transfer coefficient Ht are presented and compared with those computed numerically. An excellent agreement is obtained between the asymptotic and the numerical results. Besides, the influence of magnetic parameters on the instability of the system is also discussed. The available results in the literature are recovered as particular cases from the present study.

Hydromagnetic effects on the flow of a micropolar fluid in a diverging channel

AbstractSteady flow of an incompressible and electrically conducting micropolar fluid through a diverging channel is studied. The flow is subjected to a uniform magnetic field perpendicular to the flow direction. Perturbation solutions have been obtained for the velocity and microrotation components in terms of effective Reynolds number. The profiles of velocity and microrotation components are presented for different micropolar fluid parameters and magnetic parameter. The influence of magnetic parameter on the pressure gradient is also studied.

Influence of magnetic parameters on microwave absorption of domain mode ferromagnetic resonance

We report both theoretical and experimental results concerning the zero-field microwave absorption related to the two modes of domain mode ferromagnetic resonance (DM-FMR) which occur in unsaturated garnet films supporting parallel stripe domains. The analytical expression for the DM-FMR susceptibility, including both the anisotropy fields (uniaxial and cubic) and the effect of dissipation, is established. From this expression, the influence of magnetic parameters (quality factor, demagnetization factor of stripe domain structure, damping parameter) on the frequency dependence of the imaginary part of the susceptibility are theoretically analyzed. Power absorption measurements have been performed in the frequency range 7–12 Ghz on rare earth bismuth-substituted garnet films with different damping parameter values, and on one heat-treated sample in order to modify the value of the uniaxial anisotropy field. Satisfactory agreement between the experimental and calculated frequency dependences of the normalized zero-field power absorption is found in both cases. Nevertheless, the DM-FMR theory disagrees with the observed behaviour for one sample in the frequency range below 8 Ghz. From qualitative considerations, the hypothesis of intra-wall spin wave excitation in the vicinity of one DM-FMR mode is advanced.