Combined natural convection and radiation with temperature-dependent properties

This paper investigates the effects of temperature dependence of radiative properties of a medium on radiation and natural convection interaction in a rectangular enclosure. The radiative transfer equation is solved using the discrete ordinates method, and the momentum, continuity, and energy equations are solved by the finite volume method. Effects of the conduction-to-radiation parameter (Nr), Rayleigh number (Ra), and optical thickness are discussed. Results show that temperature dependence of radiative properties affects the temperature gradient, and hence the energy transport even in relatively weak radiation condition. On the other hand, temperature dependence of radiative properties has relatively insignificant effects on convection characteristics; even though it does affect the way that energy transfers into the system. As Nr is decreased or Ra is increased, the effects of temperature dependence of radiative properties become more significant.