Unsteady Flow of Reactive Viscous, Heat Generating/Absorbing Fluid with Soret and Variable Thermal Conductivity

I J Uwanta,M M Hamza

doi:10.1155/2014/291857

Abstract

This study investigates the unsteady natural convection and mass transfer flow of viscous reactive, heat generating/absorbing fluid in a vertical channel formed by two infinite parallel porous plates having temperature dependent thermal conductivity. The motion of the fluid is induced due to natural convection caused by the reactive property as well as the heat generating/absorbing nature of the fluid. The solutions for unsteady state temperature, concentration, and velocity fields are obtained using semi-implicit finite difference schemes. Perturbation techniques are used to get steady state expressions of velocity, concentration, temperature, skin friction, Nusselt number, and Sherwood number. The effects of various flow parameters such as suction/injection (γ), heat source/sinks (S), Soret number (Sr), variable thermal conductivityδ, Frank-Kamenetskii parameterλ, Prandtl number (Pr), and nondimensional timeton the dynamics are analyzed. The skin friction, heat transfer coefficients, and Sherwood number are graphically presented for a range of values of the said parameters.

Highlights

Natural convection flow in a porous channel in the presence of chemical reaction is important in the design of several equipment used in engineering systems, for instance in the design of nuclear reactors, thermal insulation, surface catalysis of chemical reaction, small domestic mobile winter oil heaters, and some types of radiators and hydronic heating systems
In an attempt to study the effect of chemical reaction on natural convection flows, Minto et al [1] studied natural convection flow driven by an exothermic reaction on a vertical surface embedded in porous media
The numerical results are obtained by solving (4) to (6) using the method described in the previous section for various values of physical parameters to describe the physics of the

Summary

Introduction

Natural convection flow in a porous channel in the presence of chemical reaction is important in the design of several equipment used in engineering systems, for instance in the design of nuclear reactors, thermal insulation, surface catalysis of chemical reaction, small domestic mobile winter oil heaters, and some types of radiators and hydronic heating systems. In chemical engineering and petroleum chemical industries, the interaction between chemical reaction and natural convection occurs widely Examples of such area of applications include tubular laboratory reactors, chemical vapor deposition systems, the oxidation of solid materials in large containers, the synthesis of ceramic materials by a selfpropagating reaction, combustion in underground reservoirs for enhanced oil recovery, and the reduction of hazardous combustion product using catalytic porous beds and many others. Campbell et al [2] reported the comparison of measured temperatures with those calculated numerically and analytically for an exothermic chemical reaction inside a spherical batch reactor with natural convection. They concluded that the transport of heat and mass transfer within the reactor is controlled by diffusion or natural convection.

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