APPLICATION OF STATISTICAL NARROW-BAND MODEL TO COUPLED RADIATION AND CONVECTION AT HIGH-TEMPERATURE

The use of wide-band or gray-gas models in coupled heat transfer calculations frequently leads to significant errors due to spectral correlations between the emitted flux intensity and the gas transmissivity. In the present study, a random statistical narrow-band model with an exponential-tailed inverse distribution and the Curtis-Godson approximation are used with a 25 cm** minus **1 spectral resolution; the desired parameters are generated from a line-by-line calculation. Coupled dynamic and energy equations are solved for an emitting and absorbing laminar gas flow between two parallel walls at fixed temperature. The influence of radiative and thermophysical property variations with temperature is analyzed for H//2O-air mixtures under strong temperature gradients. A large range of optical thickness is studied. Different temperature and heat flux profiles are found when the walls are heated or cooled. Finally, results obtained with the statistical narrow-band model and the exponential wide-band model are compared.