Hall Current Effects Research Articles

Unsteady nonlinear magnetohydrodynamic micropolar transport phenomena with Hall and Ion-slip current effects: Numerical study

Unsteady viscous two-dimensional magnetohydrodynamic micropolar flow, heat and mass transfer from an infinite vertical surface with Hall and Ion-slip currents is investigated theoretically and numerically. The simulation presented is motivated by electro-conductive polymer (ECP) materials processing in which multiple electromagnetic effects arise. The primitive boundary layer conservation equations are transformed into a non-similar system of coupled non-dimensional momentum, angular momentum, energy and concentration equations, with appropriate boundary conditions. The resulting two-point boundary value problem is solved numerically by an exceptionally stable and well-tested implicit finite difference technique. A stability analysis is included for restrictions of the implicit finite difference method (FDM) employed. Validation with a Galerkin finite element method (FEM) technique is included. The influence of various parameters is presented graphically on primary and secondary shear stress, Nusselt number, Sherwood number and wall couple stress. Secondary (cross flow) shear stress is strongly enhanced with greater magnetic parameter (Hartmann number) and micropolar wall couple stress is also weakly enhanced for small time values with Hartmann number. Increasing thermo-diffusive Soret number suppresses both Nusselt and Sherwood numbers whereas it elevates both primary and secondary shear stress and at larger time values also increases the couple stress. Secondary shear stress is strongly boosted with Hall parameter. Ion slip effect induces a weak modification in primary and secondary shear stress distributions. The present study is relevant to electroconductive non-Newtonian (magnetic polymer) materials processing systems.

Hall Effects on Unsteady Magneto Hydrodynamic Convection Flow of Nanofluids Past a Rotating Porous Plate

The effects of Hall current are considered for the convective rotational current free of nanofluid magnetohydrodynamics (copper and alumina) in a permeable medium with a vertical porous flat plate, semi-infinite rotation with stable state of the heat source and convection limit. The slip rate is expected to oscillate over time with a constant frequency so that the boundary layer solutions are of the equivalent oscillating type. The equations to regulate the flow are analytically solved by perturbation estimation. The effects of different parameters on the flow are investigated by means of diagrams and tables.

Mutual influences of a chemical reaction and thermal radiation on a peristaltic pump of synovial nanofluids in a 3D tapered asymmetric channel

AbstractThis investigation discusses the influences of a chemical reaction and concentration‐dependent viscosity on a magnetohydrodynamics peristaltic pump of synovial nanofluid in a tapered channel. Chemical reaction and Hall current effects are considered in the proposed investigation. The current study is solved for two suggestion models. In Model‐(I), the concentration is considered as a function in viscosity. In Model‐(II), concentration is considered as a function of the shear‐thinning index. The related study is rearranged under the models of low Reynolds number and long wavelength. The system study of highly nonlinear partial differential equations is explained mathematically with the aid of ParametricNDSolve by using Mathematica 11. Both models have been compared numerically and a huge difference is found between them. Results for velocity profile, temperature, and nanoparticle concentration distributions are obtained graphically for similar values of various physical parameters in three‐dimensional forms. Furthermore, a trapping bolus sketch is proposed in the terminus. The results confirm that the AJ patients can be cured by using the magnetic field in the presence of an electrically inducing influence, as a result of the effort of the ions inside the cell, which accelerates the metabolism of fluids. In addition, maximum values of velocity can control the friction between the joints and thus reduce arthritis.

Entropy generation analysis of Hall current effect on MHD micropolar fluid flow with rotation effect

Entropy generation in form of heat dissipation destroys useful energy which accounts for the underperformance and decrease in the thermodynamic efficiency of a system. Since micropolar fluid is used as a working fluid in many technological and industrial processes, it is therefore necessary to examine the influence of all factors that can enhance entropy production so as to achieve the best energy systems design. In this paper, the influence of Hall current and ion-slip on the entropy generation rate of micropolar fluid is investigated. An applied uniform magnetic field acts in a perpendicular direction to the flow of fluid. The nonlinear coupled partial differential equations used to model the micropolar fluid flow are transformed to ordinary differential equations by using appropriate similarity variables. The differential equations obtained are solved by applying differential transform method. The results for velocity profiles, temperature profile and microrotation are used to determine fluid irreversibility and Bejan number. To get a clearer view of the study, the effects of various parameters such as Hall, ion-slip, magnetic field and coupling number on primary velocity, secondary velocity, temperature profile, microrotation, entropy generation and Bejan number are presented and explained via plots. The results show that entropy generation is reduced as coupling number and magnetic parameter increase, Bejan number receives a boost with increase in coupling number and magnetic parameter. Furthermore, heat irreversibility is more dominant than fluid friction irreversibility at the region close to the channel walls.

Letter to the editor regarding “Hall current effect on the peristaltic motion of synovial nanofluid with magnetohydrodynamics” by Wahed M. Hasona

AbstractIn a recent work Wahed M. Hasona have analyzed the effects of Hall currents and magnetic field through a horizontal and asymmetric channel with peristaltic waves for a synovial nanofluid. The author aim was to extend some previous works. These comments has been prepared from the perspective point of view that the readers of the above mentioned paper may not be aware of the several potentially serious flawed analysis and typographical errors throughout that work. In the next few pages we will focus on some of these mistakes/typos clarifying that the obtained results should be reported as fabricated results that no one can rely upon. For this reason we wrote these comments to elaborate on some of these errors with suggested corrections for these errors to correct the literature and ensure its integrity. We first show that the mathematical formulation for the model used in this paper is not satisfactory. As a result, the obtained analytical and numerical results are inappropriate and do not match with any results for the peristaltic flow models.

The exclusive impact of Hall current over a variably thicked sheet in magnetized viscous fluid by the implementation of non-Fourier flux theory

Present study carried out the speculative investigation of Hall current effects on MHD viscous fluid flow over stretching sheet with variable thickness. For heat transfer analysis, Christov–Cattaneo heat flux model is used instead of classical Fourier law. The mathematical formulation of current flow configuration yields the set of partial differential equations with higher order of nonlinearity. The modeled partial differential equations are switched into ordinary differential equations with the aid of an appropriate set of local similarity transforms. The resulting similarity equations are tackled numerically with the assistance of fifth order Runge–Kutta integration scheme. The expressions for axial velocity, transverse velocity and temperature are numerically computed and analyzed against variations in the controlling parameters with the help of graphs. To insight flow behavior in the neighbourer region of sheet surface, local skin friction coefficients and local Nusselt number are calculated. The effects of involving flow parameters on these interesting quantities are elaborated through tabular representations. A suitable correlation of current results with previously reported data (in limiting case) is presented for the validation of computed results.

Impact of Lorentz force on free convection flow of a viscous fluid past an infinite vertical plate

In this paper, an investigation carried out to study the effects of thermal diffusion and hall current, radiation on unsteady MHD free convective viscous, incompressible, electrically conducting chemically reacting fluid past an impulsively moving infinite vertical plate embedded in a fluid saturated porous medium with variable temperature and also with variable concentration under the influence of uniform transfers applied magnetic field. The dimensionless governing partial differential equations are tackled with the usual integral transform technique without any restriction. The results illustrated graphically for the velocity, temperature and concentration distributions based on the numerical computations are performed and also discussed the effects of various physical flow parameters on the skin-friction coefficient, the rate at which heat transfer and mass transfer changes near the surface in the fluid.

Inclined Magnetic Field, Thermal Radiation, and Hall Current Effects on Mixed Convection Flow Between Vertical Parallel Plates

Abstract This analysis studies the impact of an inclined magnetic field, hall current, and thermal radiation on fully developed electrically conducting mixed convection flow through a channel. The governing equations are nondimensionalized. The resulting system of nonlinear ordinary differential equations is solved utilizing spectral quasi-linearization method. Impact of all the pertaining flow parameters of this study on all the dimensionless profiles was calculated and presented through plots. Also, the nature of the physical parameters was calculated and presented in table form. This study clearly exhibits that the inclined magnetic field influences the fluid flow remarkably.

Hall current effect on the peristaltic motion of synovial nanofluid with magnetohydrodynamics

AbstractThis paper examines the influence of magnetic field on peristaltic flow of synovial nanofluid in an asymmetric channel. Hall current, thermophoresis, and Brownian motion effects are taken into account. Our problem is discussed for two models, in the first model which referred as Model (I), viscosity is considered exponentially dependent on the concentration, and Model (II) Shear thinning index is considered function of concentration. The governing problem is reformulated under the assumption of low Reynolds number and high wavelength. Resulting system of equations are solved numerically with the aid of Parametric ND Solve. Detailed comparisons have been made between Model (I) and Model (II) and found unrealistic results between them. Results for velocity, temperature and nanoparticle concentration distributions as well as pressure gradient and pressure rise are offered graphically for different values of various physical parameters. It is found that the velocity of fluid decreases in semi‐curved lines in case of Model (I) with the increase of while, in Model (II) it decreases in the left side of the channel and increases in the right side of that channel. Such models are applicable to rheumatoid arthritis treatment.

Effectiveness of exponential heat source, nanoparticle shape factor and Hall current on mixed convective flow of nanoliquids subject to rotating frame

PurposeThe study of novel exponential heat source (EHS) phenomena across a flowing fluid with the suspension of nanoparticles over a rotating plate in the presence of Hall current and chemical reaction has been an open question. Therefore, the purpose of this paper is to investigate the impact of EHS in the transport of nanofluid under the influence of strong magnetic dipole (Hall effect), chemical reaction and temperature-dependent heat source (THS) effects. The Khanafer-Vafai-Lightstone model is used for nanofluid and the thermophysical properties of nanofluid are calculated from mixture theory and phenomenological laws. The simulation of the flow is also carried out using the appropriate values of the empirical shape factor for five different particle shapes (i.e. sphere, hexahedron, tetrahedron, column and lamina).Design/methodology/approachUsing Laplace transform technique, exact solutions are presented for the governing nonlinear equations. Graphical illustrations are pointed out to represent the impact of involved parameters in a comprehensive way. The numeric data of the density, thermal conductivity, dynamic viscosity, specific heat, Prandtl number and Nusselt number for 20 different nanofluids are presented.FindingsIt is established that the nanofluid enhances the heat transfer rate of the working fluids; the nanoparticles also cause an increase of viscous. The impact of EHS advances the heat transfer characteristics significantly than usual thermal-based heat source (THS).Originality/valueThe effectiveness of EHS phenomena in the dynamics of nanofluid over a rotating plate with Hall current, chemical reaction and THS effects is first time investigated.

Hall current effect on unsteady rotational flow of carbon nanotubes with dust particles and nonlinear thermal radiation in Darcy–Forchheimer porous media

The present discussion is about the unsteady two-dimensional flow of mixed convection and nonlinear thermal radiation in the presence of water-based carbon nanotubes over the vertically convected stretched sheet embedded in a Darcy’ Forchheimer porous media. Saffman’s proposed model is used for the suspension of fine dust particles in the nanofluid. A strong magnetic field (MHD) is applied normal to the flow which governs the Hall current effects. Khanafer Vafai Lightstone model estimated the effect of thermal conductivity and viscosity of the carbon nanotubes. Boundary layer approximation is utilized to built the nonlinear partial differential equations (PDEs). Similarity transformation is applied to convert these PDEs into the system of ordinary differential equations. Problem is solved numerically by bvp4c, using MATLAB software. It is observed through the analysis that the thermal field of nanofluid and the temperature boundary layer are much more higher than that of the dust phase, and these are further enhanced for the higher radiation parameter.

Hall current effects on MHD free convection nanofluid over an inclined hot plate with viscous dissipation

Hall current effects on MHD free convection nanofluid over an inclined hot plate with viscous dissipation

Hall current and thermophoresis effects on magnetohydrodynamic mixed convective heat and mass transfer thin film flow

The combined influences of Hall current and thermophoresis on a magnetohydrodynamic mixed convective heat and mass transfer flow of a thin film second-grade fluid with viscous dissipation and thermal radiation past a stretching sheet are analyzed. An external strong and uniform magnetic field is applied transversely to the stretching sheet. The surface of the stretching sheet is taken to move with a linear velocity and subject to the constant reference temperature and concentration. Entropy generation is introduced to investigate the irreversibility associated with flow, heat and mass transfer. The basic governing equations for the velocities, temperature and concentration of the fluid motion have been modeled by employing appropriate similarity transformations which result in high nonlinear coupled differential equations with physical conditions. The solution of the transformed systems of equations has been achieved by employing Homotopy Analysis Method (HAM) which lead to detailed expressions for the velocities, temperature and concentration components. The obtained results are compared with the published results in the tables 3–5 demonstrating an excellent agreement and correlation. Graphs are discussed to elucidate the effects of various parameters.

Entropy Generation of Carbon Nanotubes Flow in a Rotating Channel with Hall and Ion-Slip Effect Using Effective Thermal Conductivity Model.

This article examines the entropy analysis of magnetohydrodynamic (MHD) nanofluid flow of single and multiwall carbon nanotubes between two rotating parallel plates. The nanofluid flow is taken under the existence of Hall current and ion-slip effect. Carbon nanotubes (CNTs) are highly proficient heat transmission agents with bordering entropy generation and, thus, are considered to be a capable cooling medium. Entropy generation and Hall effect are mainly focused upon in this work. Using the appropriate similarity transformation, the central partial differential equations are changed to a system of ordinary differential equations, and an optimal approach is used for solution purposes. The resultant non-dimensional physical parameter appear in the velocity and temperature fields discussed using graphs. Also, the effect of skin fraction coefficient and Nusselt number of enclosed physical parameters are discussed using tables. It is observed that increased values of magnetic and ion-slip parameters reduce the velocity of the nanofluids and increase entropy generation. The results reveal that considering higher magnetic forces results in greater conduction mechanism.

Hall effect on steady mhd flow and heat transfer of a viscous fluid in a rectangular channel with suction and injection

The flow of an incompressible viscous fluid under the influence of an applied uniform magnetic field in a rectangular channel with suction at the adjacent two side walls is studied by considering Hall current and Joule heating effects. The rectangular channel is subjected to a uniform suction from top wall and injection from right wall. An external uniform magnetic field is applied perpendicular tothe flow. Two sides (left and bottom) of the channel are kept at two constant but different temperature and other two sides (right and top) are maintained at constant heat flux. Viscous and Joule dissipations are considered in the energy equation. The relevant equations of motion are solved numericallyto yield the velocity and the temperature distribution. The current density is also studied

COMPUTATION OF TRANSIENT RADIATIVE REACTIVE THERMOSOLUTAL MAGNETOHYDRODYNAMIC CONVECTION IN INCLINED MHD HALL GENERATOR FLOW WITH DISSIPATION AND CROSS DIFFUSION

The present article investigates the collective influence of chemical reaction, viscous dissipation and Hall current magnetic effects on timedependent radiative magnetohydrodynamic flow, heat and mass transfer from an inclined wall embedded in a homogenous, isotropic highpermeability porous medium. The model developed is relevant to near wall magnetohydrodynamic energy generator transport phenomena in which chemical corrosion effects may arise during operations. The governing non-linear partial differential equations for mass, momentum, energy and species conservation are transformed into a system of coupled non-linear dimensionless partial differential equations with appropriate similarity variables. The normalized conservation equations are then solved with a robust finite element method (MATLABFEM) subject to corresponding initial and boundary conditions. Important dimensionless parameters emerging are Eckert number, thermal Grashof number, solutal Grashof number, magnetic body force parameter, Hall parameter, permeability parameter, Dufour number, Soret number, time, radiation-conduction parameter, chemical reaction parameter, heat absorption parameter, Prandtl number, Schmidt number and wall angle. Primary velocity is enhanced with Eckert number, thermal Grashof number, solutal Grashof number, Hall parameter, permeability parameter, Dufour number, Soret number, radiation-conduction parameter and time whereas it is reduced with first order chemical reaction parameter, heat absorption, magnetic body force parameter, Prandtl number, Schmidt number and wall inclination. Secondary velocity is elevated with Eckert number, solutal Grashof number, thermal Grashof number, magnetic body force parameter, Hall parameter, radiation-conduction parameter, Dufour number, Soret number and time whereas it is suppressed with reaction parameter, heat absorption, Prandtl number, Schmidt number and wall inclination. Temperature is enhanced with Eckert number, Dufour number, heat absorption, radiation-conduction parameter and time whereas it is depressed with Prandtl number. Species concentration is reduced with increasing chemical reaction parameter (destructive homogenous reaction) and Schmidt number whereas it is elevated with Soret number and time. Extensive discussion of the finite element formulation, convergence and validation is provided Skin friction, Nusselt number and Sherwood number distributions are also provided for selected parameter variation. Validation of solutions with published literature is also included for several special cases, namely non-reactive, non-dissipative flow in the absence of heat generation or absorption. Further validation is included using a multi-step differential transform method (MS-DTM). The present simulations provide an interesting insight into complex fluid/thermal/species diffusion characteristics in the boundary layer region of relevance to working MHD generator systems.

Combined Influence of Hall Current and Soret Effect on Convective Heat and Mass Transfer Flow past a Vertical Porous Plate in a Rotating Fluid and Dissipation with Convective Boundary Conditions

Combined Influence of Hall Current and Soret Effect on Convective Heat and Mass Transfer Flow past a Vertical Porous Plate in a Rotating Fluid and Dissipation with Convective Boundary Conditions

Magnetohydrodynamic Ferro-Nano fluid flow in a semi-porous curved tube under the effect of hall current and nonlinear thermal radiative

Abstract Investigation of hall current as well as joule heating effects on the flow and heat transfer characteristics of Ferro-nanofluid flow through a curved tube studied in this work. This work meets a lot of engineering applications such as heat exchangers at low velocity conditions, collectors of solar energy, cooling devices of electronic and micro-electronic equipments and geophysical transport in electrically conducting. The modeling based on the momentum equations by incorporating the hall current effect as well as the energy equation by incorporating the joule heating and thermal radiative effects. Similarity transformation technique has been used to obtain non-linear ordinary differential system which solved analytically as a series solution using Differential Transformation Method (DTM) with associated of Pade approximation technique. The validation of the obtained results has been examined against a previous published works. The results confirm that the hall current has a direct and strong effect on the flow behavior, such that the presence of hall current reduces the flow pressure within the tube as well as increase the heat flux from the inner surface of the tube. Moreover a third component of velocity generates as well as a normal force called Lorentz force due to the presence of the hall current.

A numerical treatment of unsteady three-dimensional hydromagnetic flow of a Casson fluid with Hall and radiation effects

Abstract The study of the unsteady magnetohydrodynamic three-dimensional radiative flow of a viscous incompressible electrically conducting Casson liquid along a stretching surface including the effects of Hall current is presented in this article. The fluid flow model consists of time-dependent partial differential equations which are highly non-linear. Similarity transformations are utilized to obtain ordinary differential equations in similarity form. Further, a numerical approach, namely spectral quasilinearization method (SQLM), is used to solve resulting highly nonlinear ordinary differential equations. A detailed analysis is carried out to study the influences of significant parameters, such as Casson liquid parameter, Hall current parameter, magnetic parameter, unsteadiness parameter, radiative parameter, on the profiles’ of the velocity field and temperature field. The behavior of emerging quantities of engineering interest such as skin friction coefficient and the Nusselt number is also studied. Fluid flow model as presented in the paper finds applications in silicon suspensions, blood flow, polymer engineering, and printing industry.

Effect of initial stress and Hall current on a magneto-thermoelastic porous medium with microtemperatures

In this paper, the effect of initial stress on a thermoelastic porous medium with microtemperatures in the presence of magnetic field taking Hall current into account is investigated. The medium is permeated by a strong transverse magnetic field imposed perpendicularly on the displacement plane so the induced electric field is neglected. The normal mode analysis is used to obtain the exact expressions for displacement components, normal conduction current density field, transverse conduction current density field, microtemperature components, heat flux moments, stress components, temperature distribution and change in the volume fraction field. The variations of the considered variables with the horizontal distance are illustrated graphically. The results of comparisons we obtained were with and without initial stress and Hall current effect. Some particular cases of special interest have been deduced from the present investigation.