ENTROPY GENERATION ANALYSIS OF NATURAL CONVECTION IN A NON-DARCY ANISOTROPIC POROUS CAVITY

Abstract

The entropy generation associated with the natural convection in a non-Darcy anisotropic porous cavity is numerically analyzed using the finite element method (FEM). Furthermore, it is endeavored to investigate the effects of different anisotropic porous parameters on the flow, thermal field, and entropy generation. The main considered parameters in the study consist of the Rayleigh number (103 ≤ Ra ≤ 109), the Darcy number (10-2 ≤ Da ≤ 10-6), the permeability ratio (K* = 0.1,1,10), the thermal conductivity ratio (k* = 0.1,1,10), the ratio of Forchheimer constant (F* = 0.1, 1, 10), and the inclination angle of principal axis on the flow (θ = 0°, 45°, 90°). It is found that the anisotropic properties have a significant influence on the entropy generation. Change in the inclination of the principal axis θ alters the average Bejan number and the total entropy generation. The effects of ratio of the Forchheimer constant on the entropy generation and the average Bejan number appear clearly at high values of Rayleigh number. Entropy generation has the highest values in the case of high permeability ratio and low ratio of Forchheimer constant. Lower values of the average Bejan number and the total entropy gerneration are found at high values of thermal conductivity ratio. An increase of the Rayleigh number strongly enhances the total entropy generation. The entropy generation due to the fluid friction is dominant over the entropy generation due to heat transfer at high Rayleigh and Darcy numbers.