Numerical analysis of combined radiation and unsteady natural convection within a horizontal annular space

The effect of radiation on unsteady natural convection in a two-demensional participating medium between two horizontal concentric and vertically ecce ntric cylinders is investigated numerically. The equations of transfer are written by using a bicylindrical coordinates system, the stream function an d the vorticity The finite volume radiation solution method and the control volume approach are used to discretize the coupled equations of radiative transfer, momentum and energy. Original results are obtained for three ecce ntricities, Rayleigh number equal to 10(4), 10(5), and a wide range of radi ation-conduction parameter. The effects of optical thickness, wall emissivi ty and scattering on flow intensity and heat transfer are discussed.