Showing papers by "Oluwole Daniel Makinde published in 2006"

Irreversibility analysis for a gravity driven non-Newtonian liquid film along an inclined isothermal plate

Abstract: In this paper, the first and second laws of thermodynamics are employed in order to study the inherent irreversibility of a gravity driven non-Newtonian Ostwald-de-Waele power law liquid film along an inclined isothermal plate. Based on some simplified assumptions, the governing equations are obtained and solved analytically. Expressions for fluid velocity, temperature, volumetric entropy generation numbers, irreversibility distribution ratio and the Bejan number (Be) are also determined.

Thermal Ignition in a Reactive Viscous Flow Through a Channel Filled With a Porous Medium

Abstract: This paper examines the steady-state solutions of a strongly exothermic reaction of a viscous combustible material in a channel filled with a saturated porous medium under Arrhenius kinetics, neglecting reactant consumption. The Brinkman model is employed and analytical solutions are constructed for the governing nonlinear boundary-value problem using a perturbation technique together with a special type of Hermite-Pade approximants and important properties of the temperature field including bifurcations and thermal criticality are discussed.

Hydromagnetic effects on internal flow separation in a diverging channel

Abstract: In this paper, we presented the computed results for the effects of an externally applied homogeneous magnetic field on the development of internal flow separation in a two-dimensional symmetrical channel with walls parallel upstream but not parallel elsewhere. The particular example studied most fully is that of gradual exponentially diverging channel. The solution for the flow governing non-linear equation is found using perturbation method together with Pade approximation technique. Our results reveal that internal flow separation development at moderately large Reynolds number is suppressed by an increase in magnetic field intensity. The study of the flow of a viscous electrically conducting fluid through channels of varying cross section under the influence of an external magnetic field not only possessed theoretical appeal but also finds application in mathematical modelling of several industrial and biological systems. A possible practical application of the theory can be found in the field of industrial metal casting i.e. the control of molten metal flows. Another area in which the theoretical study may be of interest is in the motion of liquid metals or alloys in the cooling systems of advanced nuclear reactors. Clearly, the motion in the region with intersecting walls may represent a local transition between two parallel channels with different cross sections, a widening or a contraction of the flow. Furthermore, the study MHD flows also finds application in physiological flow problems. In recent times, many medical diagnostic devices especially those used in diagnosing cardiovascular diseases make use of the interaction of magnetic fields with tissue fluids. In a pioneering work, Hartmann and Lazarus [5] studied the influence of a transverse uniform magnetic field on the flow of a viscous incompressible electrically conducting fluid between two infinite parallel stationary and insulating plates. A survey of MHD studies in the technological fields can be found in Moreau [11]. Similarly, several authors e.g. Rao and Deshikachar [12], Makinde

Unsteady mhd flow with heat transfer in a diverging channel

Abstract: In this paper, we investigate the combined effects of unsteadiness and a transversely imposed magnetic field on viscous incompressible fluid flow and heat transfer in a slowly varying exponentially diverging symmetrical channel. The nonlinear governing equations are obtained and solved analytically using a petubation technique. Graphical results are presented and discussed quantitatively for various flow characteristics like axial velocity, temperature, axial pressure gradient, wall shear stress and Nusselt number.

Wall driven steady flow and heat transfer in a porous tube

Abstract: An incompressible axisymetric wall driven steady ∞ow of a viscous ∞uid and heat transfer in a uniformly porous tube of circular cross section is examined. For slow ∞ow and low Reynolds number, the continuity equation, the Navier Stokes equations and energy equation were solved with the aid of perturbation series. An increasing or decreasing in the acceleration Reynolds number leads to increasing or decreasing in the wall shear stress and the rate of heat transfer across the wall.

Thermal criticality in a poiseuille flow: effect of biot number

Abstract: In this paper, we investigate the effect of Biot number on thermal criticality in a strongly exothermic reaction of a viscous combustible material flowing through a channel with lower isothermal wall and upper non-isothermal wall under Arrhenius kinetics, neglecting the consumption of the material. Analytical solutions are constructed for the governing nonlinear boundary-value problem using perturbation technique together with a special type of Hermite-Pade approximants and important properties of the temperature field including bifurcations and thermal criticality are discussed.