MHD Free Convection Boundary Layer Research Articles

Hall and Ion Slip Current influence on Unsteady MHD Free Convective Boundary Layer Flow Past a Vertical Porous Plate with Thermal Radiation and Chemical Reaction

The analytical reconnaissance has been effectuated to explicate the influence of Hall and ion-slip current on nonlinear MHD free convective flow near a vertical porous plate in presence of chemical reaction and Dufour effect. In this assessment the governing PDE’s are determined analytically. The impact of multifarious physical parameters has been contemplated on velocity, temperature as well as concentration which were exemplified via numerous graphs whereas quantification for the skin fiction, nusselt number and Sherwood number are demonstrated in numeric data form and are reported in table. In this examination mainly observed that velocity declined with the incremental values of Hall current as well as ion-slip current. Meanwhile velocity as well as temperature accelerated by means of the incremental values of Dufour number. However concentration diminished with the accelerated values of chemical reaction along with Schmidt number

The Newtonian heating effect on MHD free convective boundary layer flow of magnetic nanofluids past a moving inclined plate

The effect of magnetic strength on the MHD free convection flow of nanofluids over a moving inclined plate with Newtonian heating is analyzed. The governing partial differential equations with Newtonian heating boundary conditions are transformed into a system of nonlinear coupled ordinary differential equations (ODEs) by using similarity transformations. The Keller Box method was used as a solvation method for ODEs. The skin friction and Nusselt number are evaluated analytically as well as numerically in a tabular form. Numerical results for velocity and temperature are shown graphically for various parameters of interest, and the physics of the problem is well explored. The significant findings of this study are promoting an angle of an aligned magnetic field, magnetic strength parameter, the angle of inclination parameter, local Grashof number, the volume fraction of nanoparticles, and Newtonian heating parameter. The result shows that the moving inclined plate in the same direction increases the skin friction coefficient and reduces the Nusselt number. It is also observed that the velocity of moving an inclined plate with the flow is higher compared to the velocity of moving an inclined plate against the flow. The temperature of a moving inclined plate with the flow is decreased much quicker than the temperature of a moving inclined plate against the flow. The other noteworthy observation of this study demonstrates that the Nusselt number in the Newtonian heating parameter shows that Fe3O4-kerosene is better than Fe3O4-water.

Influence of viscous dissipation and spanwise cosinusoidally fluctuating temperature on MHD free convective boundary layer flow with radiation absorption and chemical reaction

AbstractThe current reconnaissance emphasis on spanwise cosinusoidally fluctuating temperature along with time deepened as well as radiation absorption on unsteady magneto‐hydrodynamics free convective heat and mass transfer boundary layer flow with viscous dissipation, constant suction normal to an infinite hot vertical porous plate in the existence of chemical reaction by means of heat generation. The analytical solution of nonlinear PDE's governing the flow has been accomplished by employing a second‐order multiple regular perturbation method within the stipulated boundary conditions. Velocity, temperature, concentration as well as Sherwood have been exemplified graphically; along with Skin friction, and Nusselt numbers are ascertained in tabular form. Eventually, it was found that velocity, temperature, and Skin friction accelerated with the accumulative values of Eckert number and radiation absorption, but conflicting results emerged in the case of Prandtl number. Contemporaneously Sherwood's number depreciated with the magnification of the chemical reaction parameter as well as the Schmidt number.

Impact of generalized Fourier’s law and Fick’s law for MHD flow of Ag‒H2O and TiO2‒H2O nanomaterials

Purpose The purpose of this paper is to investigate the effect of inclined magnetic field, variable viscosity and Cattaneo–Christov heat and mass flux theories on the steady MHD free convective boundary layer flow of viscous, incompressible and electrically conducting water-driven silver and titanium-oxide nanofluids over a vertical stretching sheet. Design/methodology/approach The boundary layer equations of momentum, energy and nanoparticle concentration are partial differential equations in nature, which are reduced to nonlinear ordinary differential equations by means of similarity transformations. The resulting nonlinear equations are solved analytically by means of optimal homotopy analysis method. Findings Assessments with numerical results are performed and are found to be in an excellent agreement. Numerical results of the skin friction factor, the local Nusselt number and the local Sherwood number are obtained through tables. The effects of various physical parameters on the velocity, temperature and nanoparticles fraction are incorporated through graphs. The study analyzes the efficiency of heat transfer of nanofluids in cooling plants and rubber sheets. Originality/value No research works have been conducted to evaluate the effects of various physical phenomena on the copper and titanium nanofluids flow.

Unsteady MHD free convective boundary layer flow of a nanofluid past a moving vertical plate

An investigation on hydromagnetic boundary layer flow over a past an exponentially accelerated vertical plate of a nanofluid in presence of the transverse magnetic field. The fluid considered here is a non-scattering medium and the Boussinesq’s approximation is used to describe pressure gradient and radiative heat flux in the energy equation. We have considered three types of nanofluids containing Cu- water, TiO2- water and Al2O3 - water. The governing partial differential equations are transformed to dimensionless with suitable dimensional quantities and then employed Laplace transform technique in order to a closed form solution for velocity, temperature and concentration fields without any restriction. The numerical values of nanofluids on the temperature, transverse velocity, skin-friction, and Nusselt number are studies through graphs.

Chemically reacting on MHD boundary layer flow of CuO-water and MgO-water nanofluids past a stretching sheet in porous media with radiation absorption and heat generation/absorption

In the present investigation, a numerical analysis has been carried out for steady two dimensional MHD free convective boundary layer flows of electrically conducting nanofluids past a uniformly stretching sheet through porous media with radiation absorption, heat generation/absorption, thermal radiation, chemical reaction, thermo-diffusion and diffusion – thermo effects. We considered two types of nanofluids namely MgO-water and CuO-water. The mathematical model was governed by a system of linear and non-linear partial differential equations with prescribed boundary conditions. The governing boundary-layer equations are first transformed into a system of coupled nonlinear ordinary differential equations using similarity variables. The transformed equations were solved numerically by the shooting method with Runge-Kutta scheme. Finally the effects of various dimensionless governing parameters like magnetic field parameter, chemical reaction parameter, thermal radiation parameter, radiation absorption parameter, heat generation parameter, Dufour number, Soret number, volume fraction of the nanoparticles and shape of the nanoparticles on velocity, temperature and concentration profiles along with the friction factor, local Nusselt and Sherwood numbers are thoroughly studied and explicitly explained in tabular form.

Numerical analysis of MHD free convection boundary layer flow of heat and mass transfer in case of air and water

The present work has been studied the effect of various parameters on MHD boundary layer flow of heat and mass transfer in case of air and water. The governing partial differential equations are transformed to higher order ordinary differential equations by using similarity transform. This coupled ordinary differential equations are performed by shooting iteration technique along with Runge-Kutta integration scheme. The effects of various parameters on velocity, temperature and concentration profiles are discussed numerically and shown graphically. Therefore, the results of velocity field decreases for increasing values of magnetic parameter and chemical reaction parameter in case air and salt water but increases for Grashof number and modified Grashof number. The temperature field decreases in the presence of magnetic parameter but significant increasing effect for chemical reaction parameter, Grashof number and modified Grashof number in case of air and salt water. Also, the concentration profile is slightly increased for increasing the values of magnetic parameter and slightly decreased for Grashof number and modified Grashof number but significant decreasing effect are observed for reaction parameter. Finally, the numerical values of the shear stress, rate of temperature and rate of concentration are also shown in a tabular formBangladesh J. Sci. Ind. Res. 51(2), 139-146, 2016

MHD Free-Convective and Mass Transfer Flow Past a Continuously Moving Semi-Infinite Vertical Porous Plate with Thermal Diffusion

A steady two dimensional MHD free convective and mass transfer flow of an incompressible fluid past a continuously moving vertical infinite porous plate in the presence of thermal diffusion has been studied. The governing partial differential equations of the MHD free convective boundary layer flow are reduced to nonlinear ordinary differential equations by introducing suitable similarity transformations. The nonlinear similarity equations are then solved numerically by Nachtshiem-Swigert iteration technique. The results of the numerical solution are then presented graphically in the form of velocity, temperature and concentration profiles. The corresponding skin friction coefficient, the Nusselt number and the Sherwood number are also calculated and displayed in tables showing the effects of various parameters on them.

Similarity treatment for MHD free convective boundary layer flow of a class of non-Newtonian fluids

Deductive group symmetry treatment is applied to derive the similarity transformations for the free convective boundary layer flow of a class of non-Newtonian fluids past over a two-dimensional surface and flowing under the influence of transverse magnetic field. Numerical solutions are obtained for particular Non-Newtonian fluid model namely Prandtl Eyring fluid, in a graphical form . The important physical quantities like velocity distribution, skin friction coefficient and temperature variations are discussed.

Unsteady MHD Free Convection Boundary Layer Flow of Radiation Absorbing Kuvshinski Fluid through Porous Medium

An analytical study is carried out for an unsteady MHD two dimensional free convection flow of a viscous, incompressible, radiating, chemically reacting and radiation absorbing Kuvshinski fluid through a porous medium past a semi-infinite vertical plate. The dimensionless equations governing the flow are solved by simple perturbation technique. The expressions for velocity, temperature and concentration are derived. The influence of various material parameters on flow quantities are studied and discussed with the help of graphs. The expressions for Skin friction, Nusselt number and Sherwood number are also derived and discussed numerically. Temperature increases with an increase in radiation parameter and radiation absorption parameter where as it decreases with an increase in Prandtl number. Concentration is observed to be decreased when chemical reaction parameter and Schmidt number increase.

Entropy Generation in MHD Free Convective Boundary Layer Flow Past an Inclined Flat Plate Embedded in a Porous Medium with Hall Currents

An analysis of entropy generation in an MHD boundary layer flow of a viscous incompressible electrically conducting fluid past an inclined flat plate embedded in a porous media in a rotating system with Hall currents has been presented. The governing equations describing the flow have been solved analytically. The velocity field, induced magnetic field, shear stress and bulk temperature in the boundary layer flow have been discussed with the help of graphs. The entropy generation is estimated via an analytical solution of the temperature and velocity profiles obtained from the momentum and energy equations governing the flow. The Bejan number is also obtained and discussed.

Thermal diffusion and diffusion thermo effects on unsteady MHD free convection flow over a stretching surface considering Joule heating and viscous dissipation with thermal stratification, chemical reaction and Hall current

The present investigation is concerned with the effects of thermal-diffusion and diffusion-thermo on an unsteady MHD free convection boundary layer flow with heat and mass transfer of an electrically conducting fluid over a stretching sheet in the presence of strong magnetic field with Hall current, thermal stratification, chemical reaction, heat generation, thermal radiation, Joule heating and viscous dissipation. The transformed nonlinear boundary layer equations are numerically solved by applying Keller-box method. The influence of various embedded flow parameters on the local skin friction, the local Nusselt number and the local Sherwood number has been carefully analyzed through graphs. It is found that the shear stress and the rate of mass transfer increase with an increasing of current density Jh while the reverse trend is observed on the rate of heat transfer. It is also found that the shear stress and the rate of heat transfer increase with an increasing of Sr, whereas the reverse trend is observed on the rate of mass transfer. Further, the shear stress and the rate of mass transfer increase with an increasing of Du while the reverse trend is seen on the rate of heat transfer. The numerical results are compared and found to be in good agreement with previously published results under special cases.

Hall effect on MHD free convection boundary layer flow past a vertical flat plate

Effects of Hall current on MHD free convection boundary layer flow of a viscous incompressible electrically conducting fluid past a heated vertical flat plate of finite dimension in the presence of a uniform transverse magnetic field have been studied. An exact solution of the governing equations describing the flow has been obtained. The velocity field, induced magnetic field and bulk temperature distributions in the boundary layer flow have been discussed. It is found that the velocity components increase with an increase in Hall parameter. It is noticed that the induced magnetic field components are radically influenced by the Hall parameter. It is also found that the magnitude of bulk temperature in the x-direction decreases with an increase in either Hall parameter or magnetic parameter. On the other hand, the magnitude of the bulk temperature in the z-direction increases with an increase in Hall parameter whereas it decreases with an increase in magnetic parameter.

MHD free convective boundary layer flow of a nanofluid past a flat vertical plate with Newtonian heating boundary condition.

Steady two dimensional MHD laminar free convective boundary layer flows of an electrically conducting Newtonian nanofluid over a solid stationary vertical plate in a quiescent fluid taking into account the Newtonian heating boundary condition is investigated numerically. A magnetic field can be used to control the motion of an electrically conducting fluid in micro/nano scale systems used for transportation of fluid. The transport equations along with the boundary conditions are first converted into dimensionless form and then using linear group of transformations, the similarity governing equations are developed. The transformed equations are solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order method with shooting technique. The effects of different controlling parameters, namely, Lewis number, Prandtl number, buoyancy ratio, thermophoresis, Brownian motion, magnetic field and Newtonian heating on the flow and heat transfer are investigated. The numerical results for the dimensionless axial velocity, temperature and nanoparticle volume fraction as well as the reduced Nusselt and Sherwood number have been presented graphically and discussed. It is found that the rate of heat and mass transfer increase as Newtonian heating parameter increases. The dimensionless velocity and temperature distributions increase with the increase of Newtonian heating parameter. The results of the reduced heat transfer rate is compared for convective heating boundary condition and found an excellent agreement.