Unsteady MHD Flow and Heat Transfer of Dusty Fluid Between Two Cylinders With Variable Physical Properties

Author(s):  
Nagarajan Balasubramanian ◽  
Yitung Chen

A mathematical model for unsteady heat transfer and flow of an electrically conducting, viscous, incompressible dusty fluid in a channel formed between two concentric cylinders is developed. In the model, the fluid is driven along the channel by a constant pressure gradient, and an external magnetic field is applied in the direction perpendicular to the channel flow. The two cylinders are considered electrically insulated, and the surfaces maintained at constant but different temperatures with the outer cylinder being at a higher temperature. The viscosity and electrical conductivity of the fluid are considered varying with temperature. The equations governing flow and temperature distribution of both the fluid and the dust particles are a set of coupled momentum and energy equations. The derived system of non-linear partial differential equations is solved numerically on a two-dimensional computation grid using the Galerkin finite element method. The paper ends with discussions of the effect of the applied magnetic field and the variations in viscosity and electrical conductivity with temperature on the time development of the velocity and temperature distributions for both the fluid and dust particles.

Open Physics ◽  
2005 ◽  
Vol 3 (4) ◽  
Author(s):  
Hazem Attia

AbstractIn the present study, the unsteady Hartmann flow with heat transfer of a dusty viscous incompressible electrically conducting fluid under the influence of an exponentially decreasing pressure gradient is studied without neglecting the ion slip. The parallel plates are assumed to be porous and subjected to a uniform suction from above and injection from below while the fluid is acted upon by an external uniform magnetic field applied perpendicular to the plates. The equations of motion are solved analytically to yield the velocity distributions for both the fluid and dust particles. The energy equations for both the fluid and dust particles including the viscous and Joule dissipation terms, are solved numerically using finite differences to get the temperature distributions.


2006 ◽  
Vol 2006 ◽  
pp. 1-14 ◽  
Author(s):  
Hazem A. Attia

This paper studies the effect of variable viscosity on the transient Couette flow of dusty fluid with heat transfer between parallel plates. The fluid is acted upon by a constant pressure gradient and an external uniform magnetic field is applied perpendicular to the plates. The parallel plates are assumed to be porous and subjected to a uniform suction from above and injection from below. The upper plate is moving with a uniform velocity while the lower is kept stationary. The governing nonlinear partial differential equations are solved numerically and some important effects for the variable viscosity and the uniform magnetic field on the transient flow and heat transfer of both the fluid and dust particles are indicated.


2015 ◽  
Vol 7 (3) ◽  
pp. 21-31 ◽  
Author(s):  
D. R. Kuiry ◽  
S. Bahadur

The steady flow behavior of a viscous, incompressible and electrically conducting fluid between two parallel infinite insulated horizontal porous plates with heat transfer is investigated along with the effect of an external uniform transverse magnetic field, the action of inflow normal to the plates, the pressure gradient on the flow and temperature. The fluid viscosity is supposed to vary exponentially with the temperature. A numerical solution for the governing equations for both the momentum transfer and energy transfer has been developed using the finite difference method. The velocity and temperature distribution graphs have been presented under the influence of different values of magnetic inclination, fluid pressure gradient, inflow acting perpendicularly on the plates, temperature dependent viscosity and the Hartmann number. In our study viscosity is shown to affect the velocity graph. The flow parameters such as viscosity, pressure and injection of fluid normal to the plate can cause reverse flow. For highly viscous fluid, reverse flow is observed. The effect of magnetic force helps to restrain this reverse flow.


Author(s):  
Ali Mohammad Asadian ◽  
Omid Abouali ◽  
Mahmoud Yaghoubi ◽  
Goodarz Ahmadi

The present paper is concerned with the study of flow and heat transfer characteristics in the steady state free convective flow of Al2O3-waternanofluids in a square enclosure in the presence of magnetic field. Attention is given to the temperature variation of the electrical conductivity and its effect on the electromagnetic force induced by the motion of the nanofluid. A new experimental correlation recently presented in the literature was used for this aim. In all the earlier studies in this area the electrical conductivity variation of nanofluid with temperature was neglected. The fluid viscosity and thermal conductivity are assumed to vary as a function of temperature and this variation is modeled using the available experimental correlations. The governing differential equations are solved numerically using finite element method. The features of fluid flow and heat transfer characteristics are analyzed for various strengths of the magnetic field and different nanoparticle volume fractions. The results show that when the inclusion of the variation of the electrical conductivity with temperature in the numerical model noticeably affects the natural convection heat transfer in the studied rectangular cavity. The variations of Nusselt number for natural convection of Al2O3-water nanofluid with nanoparticle volume fractions are presented at various Rayleigh and Hartmann numbers.


1981 ◽  
Vol 59 (12) ◽  
pp. 1844-1850 ◽  
Author(s):  
Hyung Jae Lee ◽  
John C. Woolley

Calculations have been made using the Fletcher and Butcher method in a three conduction band model to fit a wide range of experimental transport data for n-type samples of GaSb: viz. Hall coefficient and electrical conductivity as a function of temperature and as a function of pressure at room temperature, magnetoresistance as a function of magnetic field at different temperatures, and Nernst–Ettingshausen coefficients as a function of magnetic field. Various energy gap parameters and scattering coefficients have been taken as adjustable and values determined for these which give good fits to all of the experimental data. Values of mobility for each of the Γ, L, and X bands have then been calculated as a function of temperature.


2010 ◽  
Vol 2010 ◽  
pp. 1-17 ◽  
Author(s):  
B. J. Gireesha ◽  
G. S. Roopa ◽  
C. S. Bagewadi

The present discussion deals with the study of an unsteady flow and heat transfer of a dusty fluid through a rectangular channel under the influence of pulsatile pressure gradient along with the effect of a uniform magnetic field. The analytical solutions of the problem are obtained using variable separable and Fourier transform techniques. The graphs are drawn for the velocity fields of both fluid and dust phases under the effect of Reynolds number. Further, changes in the Nusselt number are shown graphically, and, on the basis of these, the conclusions and discussions are given.


1980 ◽  
Vol 102 (4) ◽  
pp. 640-647 ◽  
Author(s):  
L. Iyican ◽  
Y. Bayazitogˇlu ◽  
L. C. Witte

The natural convection motion and the heat transfer within a trapezoidal enclosure with parallel cylindrical top and bottom walls at different temperatures and plane adiabatic sidewalls are studied. Two-dimensional natural convective fields for a range of Rayleigh numbers, up to 2.7 × 106, and enclosure tilt angles, 0 to 180 deg measured from vertical, are investigated. The Galerkin’s method of solution is applied to nonlinear form of the momentum and energy equations to determine the velocity and temperature fields. The average and local Nusselt numbers are also presented.


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