M. Ben Salah

Unstructured Control-Volume Finite-Element Method for Radiative Heat Transfer in a Complex 2-D Geometry

Abstract This article describes a new approach based on the control-volume finite-element method (CVFEM) for computing radiative heat transfer in a complex two-dimensional geometry using a general unstructured grid. To examine its accuracy and computational efficiency, five test cases are investigated, and the results obtained agree very well with other published works. In addition, the study presented in this article shows that not only this method is flexible in treating radiative heat transfer in complex geometry, but also that the computer procedure based on this numerical method needs an accurate computer process unit (CPU) time and can be combined easily with developed codes for fluid dynamics.

Anisotropy Effects on Heat and Fluid Flow by Unsteady Natural Convection and Radiation in Saturated Porous Media

ABSTRACT This article deals with a numerical study of fluid flow and heat transfer by unsteady natural convection and thermal radiation in a vertical channel opened at both ends and filled with anisotropic, in both thermal conductivity and permeability, fluid-saturated porous medium. The bounding walls of the channel are gray and kept at a constant hot temperature. In the present study we suppose the validity of the Darcy law for motion and of the local thermal equilibrium assumption. The radiative transfer equation (RTE) is solved by the finite-volume method (FVM). The numerical results allow us to represent the time–space variations of the different state variables. The sensitivity of the fluid flow and the heat transfer to different controlling parameters, namely, the single scattering albedo ω, the temperature ratio R, the anisotropic thermal conductivity ratio Rc, and the anisotropic permeability ratio Rk, are addressed. Numerical results indicate that the controlling parameters of the problem, namely, ω, R, Rc, and Rk, have significant effects on the flow and thermal field behavior and also on the transient process of heating or cooling of the medium. Effects of such parameters on time variations of the volumetric flow rate qv and the convected heat flux Q at the channels outlet are also studied.