Wall temperature difference effects on coupled double-Diffusive Natural Convection to Radiation in a square cavity

Abstract

In this paper, we study numerically the effect of wall temperature difference on the interaction between gas radiation and double-diffusive natural convection in a square cavity filled with a non-grey air-H2O mixture, at a constant average concentration of H2O (13%). Uniform temperatures and concentrations are imposed along the vertical walls, while the horizontal walls are assumed to be adiabatic and impermeable to mass transfer. The governing equations are solved by a finite-difference method and the radiative source term (in the energy equation) is evaluated by the Discrete Ordinates Method associated with the SLW spectral model of Denison and Webb. Results obtained, in aiding flow case, show that at slight walls temperature difference (ΔT= 10°C), gas radiation influences only thermal field. For a higher value (ΔT=50°C), even dynamic and concentration fields are affected. Under the gas radiation effect, convective and total heat transfers are weakened, while the mass transfer is practically insensitive.