关键词:  , 自然对流；热辐射；耦合换热；热羽流；离散坐标法

Abstract: Against the backdrop of thermal management for airborne electronic equipment, this study focuses on investigat鄄 ing the effects of wall emissivity and gas optical thickness on natural convection heat transfer of thermal plumes within a confined cavity. A numerical simulation and analysis of the temperature field, velocity field, and wall heat transfer capacity in a confined cavity filled with a radiatively participating medium were conducted using the discrete ordinate method coupled with the gray gas approximation. All cases correspond to a Rayleigh num鄄 ber (Ra) of 2.9 × 105 and a Prandtl number (Pr) of 0.71. The results indicate that thermal radiation exerts a sig鄄 nificant influence on the flow and heat transfer characteristics inside the cavity: as the gas optical thickness in鄄 creases from 0 to 20, the flow intensity and spatial thermal diffusion within the cavity gradually enhance, while the proportion of radiative heat flux in the total heat transfer on the vertical walls decreases from 71%to 12%; with the wall emissivity increasing from 0.1 to 1.0, the flow intensity and spatial thermal diffusion within the cavity gradually decrease, while the proportion of radiative heat flux in the total heat transfer on the vertical walls rises from 68%to 87%.

Key words: natural convection, thermal radiation, coupled heat transfer, thermal plume, discrete ordinate method