scholarly journals Effect of Electric Field on Dispersion of a Solute in an MHD Flow through a Vertical Channel With and Without Chemical Reaction

2016 ◽  
Vol 21 (3) ◽  
pp. 683-711
Author(s):  
J.C. Umavathi ◽  
J.P. Kumar ◽  
R.S.R. Gorla ◽  
B.J. Gireesha

Abstract The longitudinal dispersion of a solute between two parallel plates filled with two immiscible electrically conducting fluids is analyzed using Taylor’s model. The fluids in both the regions are incompressible and the transport properties are assumed to be constant. The channel walls are assumed to be electrically insulating. Separate solutions are matched at the interface using suitable matching conditions. The flow is accompanied by an irreversible first-order chemical reaction. The effects of the viscosity ratio, pressure gradient and Hartman number on the effective Taylor dispersion coefficient and volumetric flow rate for an open and short circuit are drawn in the absence and in the presence of chemical reactions. As the Hartman number increases the effective Taylor diffusion coefficient decreases for both open and short circuits. When the magnetic field remains constant, the numerical results show that for homogeneous and heterogeneous reactions, the effective Taylor diffusion coefficient decreases with an increase in the reaction rate constant for both open and short circuits.

The paper presents an analytical solution for the dispersion of a solute in a liquid flowing between two parallel plates in the presence of an irreversible first-order chemical reaction. The effects of both homogeneous and heterogeneous reactions on the dispersion are studied under isothermal conditions. It is found that for homogeneous reaction in the bulk of the liquid, the effective Taylor diffusion coefficient decreases with increase in the reaction rate constant. Further for heterogeneous reaction at the catalytic walls, Taylor diffusion coefficient is also found to decrease with increase in the wall catalytic parameter for fixed reaction rate constant corresponding to the bulk reaction.


2017 ◽  
Vol 84 (1-2) ◽  
pp. 7
Author(s):  
R. N. Barik ◽  
G. C. Dash

An analysis is made to study the eects of diusion-thermo and chemical reaction on fully developed laminar MHD ow of electrically conducting viscous incompressible uid in a vertical channel formed by two vertical parallel plates in the presence of heat source was taken into consideration with uniform temperature and concentration. The analytical solution by Laplace transform technique of partial dierential equations is used to obtain the ex- pressions for the velocity, temperature and concentration. It is interesting to note that under the in uence of dominating mass diusivity over thermal diffusivity with stronger Lorentz force reduce the velocity at all points of the channel. The increasing eect of heat source parameter leads to accelerate the velocity and decelerate the temperature. Further, the increasing eect of chemical reaction parameter enhances the velocity as well as temperature. It is observed that time span plays an important role to modify the frictional drag due to shear stress at the plates. Dufour eect and chemical reaction rate in the presence of heavier species enhance the frictional drag whereas heat source parameter leads to reduce the magnitude of frictional drag at both the plates.


2013 ◽  
Vol 19 (1) ◽  
pp. 45-55 ◽  
Author(s):  
D. Srinivasacharya ◽  
K. Kaladhar

The Soret and Dufour effects in the presence of chemical reaction on natural convection heat and mass transfer of a couple stress fluid in a vertical channel formed by two vertical parallel plates is presented. The governing non-linear partial differential equations are transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are then solved using Homotopy Analysis Method (HAM). Profiles of dimensionless velocity, temperature and concentration are shown graphically for various values of Dufour number, Soret number, Couple stress parameter and chemical reaction parameter.


2019 ◽  
Vol 8 (3S2) ◽  
pp. 994-1002

An analyticstudy has been madeof a laminar fully developed MHD flow bounded by infinite vertical parallel plates with effect of inclined magnetic fieldpartly filled with fluid and partly with porous matrix. The motions of the plates are in the opposite direction and are maintained at distinct temperatures. The perturbation method has been chosen to derive the expression for velocity flow and temperaturedistributionand the effect on flow velocity and temperature due to magnetic field and Darcy number has been illustrated for the fluid and porous region with the helpof graph.


2019 ◽  
Vol 24 (2) ◽  
pp. 269-293
Author(s):  
A.S. Idowu ◽  
U. Sani

Abstract An analysis was carried out for an unsteady magnetohydrodynamic(MHD) flow of a generalized third grade fluid between two parallel plates. The fluid flow is a result of the plate oscillating, moving and pressure gradient. Three flow problems were investigated, namely: Couette, Poiseuille and Couette-Poiseuille flows and a number of nonlinear partial differential equations were obtained which were solved using the He-Laplace method. Expressions for the velocity field, temperature and concentration fields were given for each case and finally, effects of physical parameters on the fluid motion, temperature and concentration were plotted and discussed. It is found that an increase in the thermal radiation parameter increases the temperature of the fluid and hence reduces the viscosity of the fluid while the concentration of the fluid reduces as the chemical reaction parameter increases.


2014 ◽  
Vol 3 (3) ◽  
pp. 34-42
Author(s):  
B. Lavanya ◽  
◽  
S Mohammed Ibrahim ◽  
Leela Ratnam.A ◽  
◽  
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