Numerical analysis of laminar forced convection recess flow with two inclined steps considering gas radiation effect

In this work, a numerical analysis of combined convection–radiation heat transfer over a recess including two inclined backward and forward facing steps in a horizontal duct is presented. The fluid is treated as a gray, absorbing, emitting and scattering medium. Discretized forms of the continuity, momentum and energy equations are obtained by the finite volume method and solved using the SIMPLE algorithm, while the blocked off method is employed in simulation of the inclined surfaces. The radiative transfer equation (RTE) is solved numerically by the discrete ordinates method (DOM). Numerical results reveal that the radiation–conduction parameter, optical thickness, step inclination angle and recess length have considerable effects on heat transfer behavior of the recess flow. Comparison of numerical results with the available data published in open literature shows a good consistency.