Combined mixed convection and radiation simulation of inclined lid driven cavity

This paper presents a numerical investigation of the laminar mixed convection flow of a radiating gas in an inclined lid-driven cavity. The fluid is treated as a gray, absorbing, emitting, and scattering medium. The governing differential equations including continuity, momentum and energy are solved numerically by the computational fluid dynamics techniques (CFD) to obtain the velocity and temperature fields. The discretized forms of these equations are obtained by the finite volume method and solved by using the SIMPLE algorithm. Since the gas is considered as a radiating medium, besides convection and conduction heat transfer, radiation also takes place in the gas flow. For computing the radiative term in the gas energy equation, the radiative transfer equation (RTE) is solved numerically by the discrete ordinate method (DOM). The streamline and isotherm plots and the distributions of convective, radiative and total Nusselt numbers along the bottom wall of the cavity are presented. In this work, an attempt is made to investigate the hydrodynamic and thermal behavior of the mixed convection flow of a radiating gas at different values of the cavity inclination angle. The numerical results reveal that the variation of inclination angle causes a sweep behavior in the flow pattern inside the cavity. Besides, it is found that the value of radiative Nusselt number along the heated wall has a decreasing trend when the medium optical thickness is increases. Comparisons between the present numerical results with those obtained by other investigators in the cases of conduction-radiation and pure convection systems show good consistencies.