Unsteady MHD Free Convective Heat Research Articles

Heat and Mass Transfer on Unsteady MHD Chemically Reacting Rotating Flow of Jeffrey Fluid Past an Inclined Plates under the Impact of Hall Current, Diffusion Thermo and Radiation Absorption

An analytical solution for two dimensional unsteady MHD free convective double diffusive heat and mass transfer rotating flow of viscous incompressible optically thin non Newtonian fluid (jeffrey fluid) past a semi-infinite porous plate in the presence of generation of heat absorption with hall current, radiation absorption and Dufour effects are presented in this paper. Lorentz force is applied perpendicular direction to the plate with a first-order chemical reaction. The governing PDEs transformed into ODEs by applying the perturbation technique. The effects of various physical parameters like Hall current, heat absorption, radiation parameter, radiation absorption parameter, Grashof number, modified Grashof number, Dufour effect, magnetic field parameter, inclined angle, chemical reaction parameter, etc., are studied with graphically. Temperature profile is increased by raising the values of Dufour effect, radiation absorption parameter and reverse effect of the heat absorption parameter and also concentration profile distribution is downfall by raising the values of Schmited number, chemical reaction parameter. Another significant finding of the current study is that the numerical data are displayed with the use of Matlab programmes to investigate the outcomes of the skin friction solution. the rate of heat and mass transfer at the wall rising under the influence of Dufour effect. Tables, graphs, and reports can be used to display the impact of all pertinent parameters.

Hall Current and Soret Effects on Unsteady MHD Rotating Flow of Second-Grade Fluid through Porous Media under the Influences of Thermal Radiation and Chemical Reactions

The unsteady MHD free convection heat and mass transfer flow of a viscous, incompressible, and electrically conducting fluid passing through a vertical plate embedded in a porous medium in the presence of chemical reactions and thermal radiation is investigated. The effects of the Hall current, rotation and Soret are studied. Using the perturbation approach, one can obtain an accurate analytical solution to the governing equations for the fluid velocity, fluid temperature, and species concentration, provided that the initial and boundary conditions are acceptable. It is possible to obtain expressions for the shear stress, rate of heat transfer, and rate of mass transfer for both plates with the ramping temperature and isothermal conditions. On the one hand, the numerical values of the primary and secondary fluid velocities, fluid temperature, and species concentration are presented graphically. On the other hand, the numerical values of the shear stress and rate of mass transfer for the plate are presented in tabular form for various values of the relevant flow parameters. These values are given for a range of pertinent flow parameters. It was determined that an increase in the Hall and Soret parameters over the whole fluid area leads to a corresponding increase in the resulting velocity. The resultant velocity continually climbs to a high level due to the contributions of the thermal and solute buoyancy forces. Lowering the heat source parameter reduces the temperature distribution, resulting in a lower overall temperature. When there is a rise in the chemical reaction parameter over the whole fluid area, there is a corresponding decrease in the concentration. The concentration buoyancy force, Hall current, and Prandtl number reduce the skin friction. On the other hand, the permeability of the porous medium, rotation, chemical reaction, the Soret number, thermal buoyancy force, and mass diffusion all have the opposite effects on the skin friction.

Hall, Soret, and rotational effects on unsteady MHD rotating flow of a second-grade fluid through a porous medium in the presence of chemical reaction and aligned magnetic field

The effects of Hall current, rotation and Soret effects on an unsteady MHD free convection heat and mass transfer flow of a viscous, incompressible and electrically conducting fluid past an inclined plate embedded in a porous medium in the presence of chemical reaction and an aligned magnetic field are investigated. An exact analytical solution of the governing equations for fluid velocity, fluid temperature, and species concentration subject to appropriate initial and boundary conditions is obtained using the perturbation technique. Expressions for shear stress, rate of heat transfer and rate of mass transfer at the plate are derived for both ramped temperature and isothermal plates. The numerical values of primary and secondary fluid velocities, fluid temperature and species concentration are displayed graphically, whereas those of shear stress and rate of mass transfer at the plate are presented in tabular form for various values of pertinent flow parameters. It is concluded that, the resultant velocity is increased with an increasing in Hall and Soret parameters throughout fluid region. The thermal and solutal buoyancy forces contribute to the resultant velocity ever-increasing to high. The temperature distribution is trim downs through an increasing in heat source parameter. The concentration is reduced with an increase in the chemical reaction parameter in the entire fluid region. Concentration buoyancy force, hall current, and Prandtl number have tendency to reduce in skin friction whereas permeability of the porous medium, Rotation, chemical reaction, Soret number, thermal buoyancy force and mass diffusion have reverse effect on it.

Effectiveness of magnetize flow on nanofluid via unsteady natural convection inside an inclined U-shaped cavity with discrete heating

This analysis investigates the unsteady MHD free convection flow and heat transfer in an inclined U-shaped cavity filled with Cu-water nanofluid. Both the right and left walls of the cavity and the internal walls of the cavity are supposed to be adiabatic, while the upper horizontal walls of the cavity are kept at a lower temperature. A heat source is located on the bottom horizontal wall with its position that alters the left vertical wall. The dimensionless governing equations are solved using the Successive Under-Relaxation technique. The investigation is achieved by controlling the impact of a set of pertinent parameters, namely; the size and position of the heat element (B = 0.3–0.6, D = 0.3–0.6), Hartman number (Ha = 0–50), nanoparticle volume fraction (ϕ = 0.0–0.07), heat source generation/ absorption (Q = −4.0–2.0), and aspect ratio (AR = 0.2–0.6). The results show that the mean Nu declines with heat source length and Hartmann number, whereas it augments with dimensionless heat source location. Furthermore, the mean Nu rises in parallel with the solid volume fraction of nanoparticles and decreases with aspect ratio. In addition, the increasing of aspect ratio reduces the convection mode compared to conduction heat transfer.

Heat and Mass Transfer Analysis of an Unsteady MHD Flow Past an Impulsively Started Vertical Plate in Presence of Thermal Radiation

The present paper aims at investigating the boundary layer flow of an unsteady MHD free convection heat and mass transfer flow of a viscous, incompressible and electrically conducting fluid over an impulsively started infinite vertical plate in presence of thermal radiation. The magnetic Reynolds number is considered to be so small that the induced magnetic field can be neglected. Exact solution of the governing equations is obtained in closed form by Laplace transform technique. Expression for skin friction, Nusselt number and Sherwood number are derived. The numerical values of fluid velocity, fluid temperature and species concentration are displayed graphically whereas the numerical values of skin friction, the Nusselt number and the Sherwood number are presented in tabular form for various values of pertinent flow parameters. It is being found that the mass diffusion tends to reduce the fluid velocity whereas thermal radiation has reverse effect on the fluid velocity throughout the boundary layer region. Mass diffusion tends to reduce the species concentration whereas time has reverse effect on the species concentration throughout the boundary layer region. The radiation parameter and mass diffusion decreases the skin friction whereas Prandtl number has reverse effect on it. The radiation parameter reduces the rate of heat transfer whereas as time progress the rate of heat transfer is getting accelerated.

A Study of Chemically Reactive Species and Thermal Radiation Effects on an Unsteady MHD Free Convection Flow Through a Porous Medium Past a Flat Plate with Ramped Wall Temperature

An investigation of the effects of a chemical reaction and thermal radiation on unsteady MHD free convection heat and mass transfer flow of an electrically conducting, viscous, incompressible fluid past a vertical infinite flat plate embedded in a porous medium is carried out. The flow is induced by a general time-dependent movement of the vertical plate, and the cases of ramped temperature and isothermal plates are studied. An exact solution of the governing equations is obtained in closed form by the Laplace Transform technique. Some applications of practical interest for different types of plate motions are discussed. The numerical values of fluid velocity, temperature and species concentration are displayed graphically whereas the numerical values of skin friction, Nusselt number and Sherwood number are presented in a tabular form for various values of pertinent flow parameters for both ramped temperature and isothermal plates.

Unsteady MHD Free Convective Heat and Mass Transfer Flow Past a Vertical Porous Plate in the Presence of Radiation and Chemical Reaction

The objective of this paper is to analyze an unsteady MHD free convective heat and mass transfer boundary flow past a semi-infinite vertical porous plate immersed in a porous medium with radiation and chemical reaction. The governing equations of the flow field are solved numerical a two term perturbation method. The effects of the various parameters on the velocity, temperature and concentration profiles are presented graphically and values of skin-frication coefficient, Nusselt number and Sherwood number for various values of physical parameters are presented through tables.

Unsteady MHD free convective heat and mass transfer flow with variable heatand mass fluxes

Unsteady MHD free convective heat and mass transfer flow with variable heatand mass fluxes

Free convective heat transfer with hall effects, heat absorption and chemical reaction over an accelerated moving plate in a rotating system

The unsteady MHD free convective heat and mass transfer flow of an electrically conducting, viscous and incompressible fluid over an accelerated moving vertical plate in the presence of heat absorption and chemical reaction with ramped temperature and ramped surface concentration through a porous medium in a rotating system is studied, taking Hall effects into account. The governing equations are solved analytically with the help of Laplace transform technique. The unified closed-form expressions are obtained for fluid velocity, fluid temperature, species concentration, skin friction, Nusselt number and Sherwood numbers. The effects of various parameters on fluid velocity, fluid temperature and species concentration are discussed by graphs whereas numerical values of skin friction, Nusselt and Sherwood numbers are presented in tabular form for different values of pertinent flow parameters. The numerical results are also compared with free convective flow near ramped temperature plate with ramped surface concentration with the corresponding flow near isothermal plate with uniform surface concentration.

Effects of Hall current, rotation and Soret effects on MHD free convection heat and mass transfer flow past an accelerated vertical plate through a porous medium

Abstract The effects of Hall current, rotation and Soret effects on an unsteady MHD free convection heat and mass transfer flow of a viscous, incompressible and electrically conducting fluid past an infinite vertical plate embedded in a porous medium are investigated. It is assumed that the entire system rotates with a uniform angular velocity Ω ′ about the normal to the plate and a uniform transverse magnetic field is applied along the normal to the plate directed into the fluid region. The magnetic Reynolds number is considered to be so small that the induced magnetic field can be neglected. Exact solution of the governing equations is obtained in closed form by Laplace transform technique. Exact solution is also obtained in case of unit Schmidt number. The expressions for primary and secondary fluid velocity, fluid temperature, species concentration, skin friction due to primary and secondary velocity fields at the plate are obtained.

Radiation and mass transfer effects on MHD flow through porous medium past an exponentially accelerated inclined plate with variable temperature

Abstract An analysis of unsteady MHD free convection flow, heat and mass transfer past an exponentially accelerated inclined plate embedded in a saturated porous medium with uniform permeability, variable temperature and concentration has been carried out. The novelty of the present study was to analyze the effect of angle of inclination on the flow phenomena in the presence of heat source/sink and destructive reaction. The Laplace transformation method has been used to solve the governing equations. The effects of the material parameters, magnetic field and the permeability of the porous medium are discussed. From the present analysis it is reported that the presence of magnetic field and porous medium prevents the flow reversal. Angle of inclination and heat source sustains a retarding effect on velocity. The present study has an immediate application in understanding the drag experienced at the heated/cooled and inclined surfaces in a seepage flow.

Theoretical Investigation of an Unsteady MHD Free Convection Heat and Mass Transfer Flow of a Non-Newtonian Fluid Flow Past a Permeable Moving Vertical Plate in the Presence of Thermal Diffusion and Heat Sink

The problem of unsteady, two-dimensional, laminar, boundary-layer flow of a viscous, incompressible, electrically conducting and heat-absorbing Rivlin-Ericksen flow fluid along a semi-infinite vertical permeable moving plate has been investigated. A uniform transverse magnetic field is applied in the direction of the flow. The presence of thermal and concentration buoyancy effects is considered. The plate is assumed to move with a constant velocity in the direction of fluid flow while the free stream velocity is assumed to follow the exponentially increasing small perturbation law. Time-dependent wall suction is assumed to occur at the permeable surface. The dimensionless governing equations for this investigation are solved analytically using two-term harmonic and non-harmonic functions. Numerical evaluation of the analytical results is performed and some graphical results for the velocity, temperature and concentration distributions within the boundary layer are presented. Skin-friction coefficient, Nusselt number and Sherwood number are also discussed with the help of the graphs. Local skin-friction coefficient increases with an increase in the permeability parameter, and Soret number whereas reverse effects is seen in the case of dimensionless viscoelasticity parameter of the Rivlin-Ericksen fluid. Nusselt number decreases in the presence of heat absorption. The presence of Soret number Sherwood number increases.

Unsteady MHD Free Convective Heat and Mass Transfer in a Boundary Layer Flow Past a Vertical Permeable Plate with Thermal Radiation and Chemical Reaction

In this present article, we analyzed the nonlinear unsteady MHD flow of viscous, incompressible and electrically conducting fluid past a vertical porous channel under the influence of thermal radiation and chemical reaction. The transformed conservation equations are solved analytically subject to physically appropriate boundary conditions by using two term perturbation technique. The influence of a number of emerging non-dimensional parameters namely, Magnetic parameter, Prandtl number, Chemical reaction parameter, Thermal radiation parameter and Schmidt number examined in detail. Furthermore, the influence of these parameters on heat transfer rate and skin friction is also investigated. It is observed that the velocity is decreased with increasing chemical reaction parameter. Increasing rarefaction parameter increases the velocity and but increasing suction parameter decreases the velocity. The study is relevant to chemical materials processing applications.

English

An analysis of thermal radiation effects on unsteady MHD free convective heat and mass transfer flow past a vertical porous plate immersed in a porous medium with time dependent suction in presence of magnetic field with viscous dissipation has been considered by employing shooting iteration technique along with fourth order Runge- Kutta integration scheme. Resulting non-dimensional velocity, temperature and concentration profiles are then presented graphically for different values of the parameters entering into the problem. Finally, the effects of the pertinent parameters on the skin-friction coefficient, the rate of heat transfer (Nusselt number) and the rate of mass transfer (Sherwood number), which are of physical interest, are exhibited in the tabular form.

Effects of Thermal Diffusion and Viscous Dissipation on Unsteady MHD Free Convection Flow Past a Vertical Porous Plate Under Oscillatory Suction Velocity with Heat Sink

The thermal diffusion and viscous dissipation effects on an unsteady MHD free convection heat and mass transfer flow of an incompressible, electrically conducting, fluid past an infinite vertical porous plate embedded in a porous medium of time dependent permeability under oscillatory suction velocity in the presence of a heat absorbing sink have been studied. It is considered that the influence of a uniform magnetic field acts normal to the flow and the permeability of the porous medium fluctuates with time. The dimensionless governing equations for this investigation have been solved numerically by using the efficient Galerkin finite element method. The numerical results obtained have been presented through graphs and tables for the thermal Grashof number (Gr > 0) corresponding to the cooling of the porous plate and (Gr < 0) corresponding to heating of the porous plate to observe the effects of various material parameters encountered in the problem under investigation. Numerical data for skin-friction, Nusselt and Sherwood numbers are tabulated and then discussed.

Effects of Binary Chemical Reaction and Activation Energy on MHD Boundary Layer Heat and Mass Transfer Flow with Viscous Dissipation and Heat Generation/Absorption

We study an unsteady MHD free convection heat and mass transfer boundary layer incompressible fluid flow past a vertical porous plate in the presence of viscous dissipation, heat generation/absorption, chemical reaction, and Arrhenius activation energy. The plate is moving with uniform velocity. The chemical reaction rate in the function of temperature is also considered. The governing partial differential equations are reduced to ordinary differential equations by introducing local similarity transformation (Maleque (2010)) and then are solved numerically by shooting method using the Nachtsheim-Swigert iteration technique. The results of the numerical solution are then presented graphically as well as the tabular form for difference values of the various parameters.

Unsteady MHD double-diffusive convection boundary-layer flow past a radiate hot vertical surface in porous media in the presence of chemical reaction and heat sink

This paper presents an analytical study of the unsteady MHD free convective heat and mass transfer flow of a viscous, incompressible, gray, absorbing-emitting but non-scattering, optically-thick and electrically conducting fluid occupying a semi-infinite porous regime adjacent to an infinite moving hot vertical plate with constant velocity. We employ a Darcian viscous flow model for the porous medium the Rosseland diffusion approximation is used to describe the radiative heat flux in the energy equation. The homogeneous chemical reaction of first order is accounted in mass diffusion equation. The governing equations are solved in closed form by Laplace-transform technique. A parametric study of all involved parameters is conducted and representative set of numerical results for the velocity, temperature, concentration, shear stress function \(\frac{\partial u}{\partial y} \vert_{y=0}\), temperature gradient \(\frac{\partial \theta }{ \partial y}\vert_{y=0}\), and concentration gradient \(\frac{ \partial \phi }{\partial y}\vert_{y=0}\) is illustrated graphically and physical aspects of the problem are discussed.

Heat And Mass Transfer Effects On Unsteady MHD Free Convection Flow Past a Vertical Permeable Moving Plate with Radiation

In this analysis, the effects of radiation have been discussed on unsteady MHD free convection heat and mass transfer flow on a viscous, incompressible, electrically conducting fluid past a vertical permeable moving plate with radiation. The non-linear partial differential equations governing the flow have been solved numerically using finite element method. Graphical results for velocity, temperature and concentration profiles have been obtained, to show the effects of different parameters entering in the problem. Such flow problems are important in many processes, in which there is combined heat and mass transfer with radiation. It has been observed that the velocity increase with the increase in the radiation parameter and there is a increase in temperature with the increase in the value of radiation parameter.

Finite Element Analysis of Heat and Mass Transfer Effects on Unsteady MHD Free Convection Flow past a Vertical Permeable Moving Plate with Radiation

The paper examined the radiation effect on unsteady MHD free convection heat and mass transfer flow on a viscous, incompressible, electrically conducting fluid past a vertical permeable moving plate with radiation. The non-linear partial differential equations governing the flow have been solved numerically using finite element method. Graphical results for velocity, temperature and concentration profiles have been obtained, to show the effects of different parameters entering in the problem. Such flow problems are important in many processes, in which there is combined heat and mass transfer with radiation. It has been observed that the velocity increase with the increase in the radiation parameter and there is a increase in temperature with the increase in the value of radiation parameter. Keywords: Heat and Mass transfer, MHD, Radiation, FEM

Finite Element Analysis of Heat and Mass Transfer Effects on Unsteady MHD Free Convection Flow past a Vertical Permeable Moving Plate with Radiation

The paper examined the radiation effect on unsteady MHD free convection heat and mass transfer flow on a viscous, incompressible, electrically conducting fluid past a vertical permeable moving plate with radiation. The non-linear partial differential equations governing the flow have been solved numerically using finite element method. Graphical results for velocity, temperature and concentration profiles have been obtained, to show the effects of different parameters entering in the problem. Such flow problems are important in many processes, in which there is combined heat and mass transfer with radiation. It has been observed that the velocity increase with the increase in the radiation parameter and there is a increase in temperature with the increase in the value of radiation parameter. Keywords: Heat and Mass transfer, MHD, Radiation, FEM