Numerical Simulation of Forced Convection Duct Flow of a Radiating Gas with Separation

In this paper, a numerical study of a 2-D combined convection-radiation heat transfer in a horizontal rectangular duct with two sudden contractions is presented. Contractions in duct are created by two inclined forward facing steps. To simulate the incline surfaces of the FFS, the blocked- off method was employed for both fluid mechanic and radiation problems. The fluid was treated as a gray, absorbing, emitting and scattering medium. To solve the governing equations, the 2-D Cartesian coordinate system was used. These equations were solved numerically, using the CFD techniques and SIMPLE algorithm. For computation of radiative term in energy equation, the radiative transfer equation (RTE) was solved numerically by discrete ordinates method (DOM) to find the divergence of radiative heat flux distribution. The effects of optical thickness, radiation-conduction parameter and albedo coefficient on heat transfer behavior of the system were carried out. Comparison of numerical results with available credential data shows good consistency.