Three dimensional simulation of convection and radiation in a cubic cavity

چکیده مقاله

The main objective of this study is to investigate the phenomenon of radiation and natural convection in both transparent and participating media in a three-dimensional differentially heated cavity. The radiative transfer equation was solved using the discrete ordinates method. The Navier–Stokes equations, proposed for natural convection, were solved using a segregated SIMPLE-like algorithm. For non-participating media, the coupling between the radiative transfer and Navier–Stokes equations was carried out via the radiative heat exchange between surfaces. For participating media, a source term is added in the energy equation. In the cases of transparent and participating media with different optical thicknesses, the local and mean heat flux as a function of the Rayleigh number was studied. The heat flux was also analyzed for different values of the Rayleigh number in order to investigate the effect of the Planck number. The results obtained in the mid-plane of a long rectangular enclosure were compared to a purely two-dimensional case. It has been shown that the radiation significantly increases the heat flux in a transparent medium and that for a given Planck number and constant reference temperature ratio, the contribution of radiation remains almost constant for a variety range of Rayleigh numbers.