INTERACTION OF SURFACE RADIATION WITH NATURAL CONVECTION AIR COOLING OF DISCRETE HEATERS IN A VERTICAL RECTANGULAR ENCLOSURE

للكاتبين :

R.Y. Sakr1 and T.A. Ahmed2

1 Mech. Eng. Dept., Shoubra Faculty of Engineering, Benha University, Egypt

2 Mech. Power Eng. Dept., Faculty of Engineering , Cairo University, Egypt

ABSTRACT

This paper presents a numerical study that concerning the effect of surface radiation on

natural convection cooling of four discrete isoflux heaters flush-mounted on a vertical wall

of an air filled rectangular enclosure. The opposite side is isothermally cooled while the

top and bottom sides as well as the spacing between the heaters are kept adiabatic. Twodimensional

mathematical model was developed based on solving the partial differential

equations for the conservation of mass, momentum, and energy. A laminar flow is to be

considered in the present model. Galerkin finite element method was utilized for the model

formulation.

A numerical simulation is carried out to examine the parametric effects of enclosure aspect

ratio, Rayleigh number, heater emissivity, adiabatic and cold surfaces emissivities, and the

radiation parameter on the role played by the surface radiation in heat dissipation from the

discrete heaters in the enclosure. The computed model results were verified through the

comparison with those experimental results available in the literature and good agreement

between them were noticed.

Several correlation equations in terms of aspect ratio, Rayleigh number, heater surface

emissivity and the radiation parameter for the average Nusselt number for heaters, its

radiative and convective components as well as the maximum surface temperature at the

discrete heaters are obtained.

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