Effects of Non-Gray Radiating Gases on Mixed Convection Heat Transfer in an Inclined Duct with Separation

In this research, the effects of non-gray radiating gases on mixed forced and free convection heat transfer in an inclined duct with separation are studied. Distributions of absorption coefficients across the spectrum are obtained from the HITRAN2008 database. The full-spectrum k-distribution method (FSK) is used to account for non-gray radiation properties, while the gray radiation calculations are carried out using the Planck mean absorption coefficient. In addition, the effects of duct inclination on the hydrodynamic and thermal behaviors of fluid flow are presented graphically for both gray and non-gray medium situations. The results show that increasing in the duct inclination leads to a considerable increase in the values of friction coefficient, and convective, radiative and total Nusselt numbers. Also, the results of gray medium are compared with non-gray results as a real case. This comparison illustratesthat the difference between the results of these mediums enhances by increasing the duct inclination, such that the highest difference between the results is related to the vertical ducts.