Buoyancy Force Influence on the Hydrodynamics and Thermal Behaviors of Mixed Convection Flow of a Radiating Gas in a Duct with Recess

In the present research, the effects of buoyancy force and radiative parameters on the hydrodynamic and thermal behaviors of mixed convection flow of a radiating gas in an inclined two-dimensional duct with a trapezoidal recess are studied and investigated. This recess is created inside the duct by two inclined backward and forward facing steps. For modeling the inclined surfaces of this recess in the Cartesian coordinates, the Blocked region method is used. To obtain the velocity and temperature fields, the dimensionless forms of the governing equations are solved using the finite volume method and by applying the Simple algorithm. The discrete-ordinates method is used to calculate the divergence of the radiative heat flux in the energy equation. The results of the numerical solution show that with increasing the Grashof number and duct inclination angle, the values of the mean bulk temperature along the recess and also the values of the friction coefficient and heat transfer rates on the bottom wall of recess increase. Besides, an increase in the magnitudes of radiation-conduction parameter and optical thickness results in an enhancement in the values of the mean bulk temperature and total Nusselt number along the bottom wall of recess; while these values decrease by increasing the magnitudes of albedo coefficient.