Analysis of Combined Radiation and Forced Convection Heat Transfer in 3D Laminar Flow over an Inclined Forward Facing Step

Abstract

In the current study, a numerical investigation of three-dimensional combined convection-radiation heat transfer over an inclined forward facing step (FFS) in a horizontal rectangular duct is presented. The fluid is treated as a gray, absorbing, emitting and scattering medium. To simulate the incline surface of FFS, the blocked-off method is employed in this study. The set of governing equations for gas flow are solved numerically using the CFD technique to obtain the temperature and velocity fields. Since the gas is considered as a radiating medium, all of the convection, conduction and radiation heat transfer mechanisms are presented in the energy equation. For computation of radiative term in energy equation, the radiative transfer equation (RTE) is solved numerically by the discrete ordinates method (DOM) to find the divergence of radiative heat flux distribution inside the radiating medium. The effects of optical thickness, radiation-conduction parameter and albedo coefficient on heat transfer behavior of the system are carried out.

Modeling of thermal radiation in a participating media with conjugate heat transfer

“…To compare the results, the distribution of $${\text{Nu}}_{{\rm{c}}}$$ over the upstream of the step is plotted in (Figure 3B). Both the obtained result and the results from Rayeni and Nassab 45 are closely matching. Hence, it is confirmed that the code can model RHT.…”

“…The RHT part of the analysis was validated from the research paper results of Rayeni and Nassab 45 by considering a laminar flow over a 3D FFS. Geometry with actual boundary conditions specified by Rayeni and Nassab 45 are given in Figure 3A.…”

“…The RHT part of the analysis was validated from the research paper results of Rayeni and Nassab 45 by considering a laminar flow over a 3D FFS. Geometry with actual boundary conditions specified by Rayeni and Nassab 45 are given in Figure 3A. For validating RHT, the flow parameters considered are N = 1006, Re = 250, $$\omega =0.5$$, and $$\tau =0.05$$.…”

“…Hence, it is confirmed that the code can model RHT. For this validation of RHT we have considered only the upstream result from the paper by Rayeni and Nassab 45 because they have considered a 45° inclined step and in this study, we do not have any inclination, so the distribution of $${\text{Nu}}_{{\rm{c}}}$$ on the step is different in both cases.…”