Diffusion-Thermo Effects on Hydromagnetic Free Convection Heat and Mass Transfer Flow through High Porous Medium Bounded by a Vertical Surface

The objective of this work is to study the Diffusion-thermo effect (Dufour effect) on unsteady MHD free convective heat and mass transfer flow of a viscous incompressible electrically conducting, radiating and chemically reacting fluid past a semi-infinite vertical permeable plate embedded in high porous medium with time dependent suction. A uniform magnetic field of strength  is applied in the transverse direction to the fluid flow. The dimensionless governing equations are solved by a regular perturbation technique. The effect of flow parameters on velocity, temperature, concentration, the rate of heat transfer, the rate of mass transfer and the skin friction coefficients are shown in graphical and tabular forms.  It is observed that the effect of Dufour number on temperature and velocity field is significant near the plate. Keywords: chemical reaction, MHD, porous medium, radiation and Dufour number

Dufour Effect On MHD Free Convection Flow of Chemically Reactive and Radiation Absorption Fluid Past a Vertical Permeable Moving Plate with Variable Suction

Electrically conducting, chemically reacting and heat generation/absorbing fluid flow through a porous medium is examined over a semi-infinite vertical permeable surface in the presence of a radiation absorption and diffusion-thermo effects. The plate is assumed to move with a constant velocity in the direction of fluid flow. A uniform magnetic field of strength is applied perpendicular to the porous surface, which absorbs the fluid with a variable suction velocity. The dimensionless governing equations are solved analytically using two term harmonic and non-harmonic functions. The effect of velocity, temperature, concentration, skin friction coefficient, Nusselt number and Sherwood number for different flow parameters are shown in graphical and tabular forms. Keywords: Chemical reaction; Mass diffusion; Radiation absorption; Diffusion-thermo (Dufour number)

Dufour and Thermal Radiation Effects of Kuvshinski Fluid on Double Diffusive and Convective MHD Heat and Mass Transfer Flow Past a Porous Vertical Plate in the Presence of Radiation Absorption, Viscous Dissipation and Chemical Reaction

In this paper an analysis is presented to investigate the influence of diffusion thermo, thermal radiation, radiation absorption, chemical reaction and viscous dissipation on hydro magnetic free convective heat and mass transfer flow of Kuvshinski fluid past a porous vertical plate. A uniform magnetic field of is applied in the direction of the flow field.  Analytical solutions for velocity, temperature and concentration are obtained by using a Perturbation technique. Skin friction, rate of heat and mass transfer coefficients are also derived. The results have been analyzed graphically and numerically for various values of the flow parameters

Free convective MHD flow past a vertical cone with variable heat and mass flux

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.A numerical study of buoyancy-driven unsteady natural convection boundary layer flow past a vertical cone embedded in a non-Darcian isotropic porous regime with transverse magnetic field applied normal to the surface is considered. The heat and mass flux at the surface of the cone is modeled as a power-law according to q_W (x)= x^m respectively, where x denotes the coordinate along the slant face of the cone. Both Darcian drag and Forchheimer quadratic porous impedance are incorporated into the two-dimensional viscous flow model. The transient boundary layer equations are then non-dimensionalized and solved by the Crank-Nicolson implicit difference method. The velocity, temperature and concentration fields have been studied for the effect of Grashof number, Darcy number, Forchheimer number, Prandtl number, surface heat flux power-law exponent (m), surface mass flux power-law exponent (n), Schmidt number, buoyancy ratio parameter and semi-vertical angle of the cone. Present results for selected variables for the purely fluid regime are compared with the published results and are found to be in excellent agreement. The local skin friction, Nusselt number and Sherwood number are also analyzed graphically. The study finds important applications in geophysical heat transfer, industrial manufacturing processes and hybrid solar energy systems. To test the accuracy of the computations the local shear stress and local Nusselt number computations for the non-porous case are compared with those of Hossain and Paul [9] for a heat flux gradient of m = 0.5 and X = 1.0 in the steady state, and are found to be in good agreement.dc201

Unsteady MHD Radiative and Chemically Reactive Free Convection Flow near a Moving Vertical Plate in Porous Medium

We have investigated an unsteady flow of a viscous, incompressible electrically conducting, laminar free convection boundary layer flow of a moving infinite vertical plate in a radiative and chemically reactive medium in the presence of a transverse magnetic field. The equations governing the flow are solved by Laplace transform technique. The expressions for velocity, temperature, concentration are derived and based on these quantities the expressions for skin friction; rate of heat transfer and the rate mass transfer near the plate are derived. The effects of various physical parameters on flow quantities, wise magnetic parameter, Grashof number, modified Grashof number, heat source parameter, the chemical reaction parameter, Schmidt number and radiation parameter are studied numerically and the results are discussed with the help of graphs. Some important applications of physical interest for different type motion of the plate like case (i) when the plate is moving with uniform velocity, case (ii) when the plate is moving with single acceleration and case (iii) when the plate is moving with periodic acceleration, are discussed

Chemical Reaction and Radiation Effects on the Hydro-Magnetic Free Convection Flow of Visco-Elastic Fluid along an Infinite Vertical Porous Plate in a Porous Medium

An unsteady hydro magnetic laminar free convection heat and mass transfer flow of a visco-elastic, dissipative fluid along an infinite vertical Porous plate through porous medium is analyzed in the presence of chemical reaction and thermal radiation.  The solution of the problem is obtained in the form of power series of  which is very small. Analytical expressions for the velocity, temperature and concentration fields are given, as well as for the skin friction, the rate of heat transfer and the rate of mass transfer coefficient at the plate.  The influence.......

Heat transfer effects on a viscous dissipative fluid flow past a vertical plate in the presence of induced magnetic field

A theoretical analysis is performed to study induced magnetic field effects on free convection flow past a vertical plate. The x¯-axis is taken vertically upwards along the plate, y¯-axis normal to the plate into the fluid region. It is assumed that the plate is electrically non-conducting and the applied magnetic field is of uniform strength (H0) and perpendicular to the plate. The magnetic Reynolds number of the flow is not taken to be small enough so that the induced magnetic field is taken into account. The coupled nonlinear partial differential equations are solved by Perturbation technique and the effects of various physical parameters on velocity, temperature, and induced magnetic fields are studied through graphs and tables. Variations in Skin friction and rate of heat transfer are also studied. It is observed that an increase in magnetic parameter decreases the velocity for both water and air. It is also seen that there is a fall in induced magnetic field as magnetic Prandtl number, and magnetic field parameter increase

Unsteady Three-Dimensional MHD Nanofluid Flow Over a Stretching Sheet with Variable Wall Thickness and Slip Effects

The stretching sheets with variable thickness may occur in engineering applications more frequently than a flat sheet. Due to its various applications, in the present analysis we considered a three dimensional unsteady MHD nanofluid flow over a stretching sheet with a variable wall thickness in a porous medium. The effects of radiation, viscous dissipation and slip boundary conditions are considered. Buongiorno’s model is incorporated to study the combined effects of thermophoresis and Brownian motion. The dimensionless governing equations are solved by using MATLAB bvp4c package. The impact of various important flow parameters is presented and analysed through graphs and tables. It is interesting to note that all the three boundary layer thicknesses are diminished by slip parameters. Further, the unsteady parameter decreases the hydromagnetic boundary layer thickness