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Numerical analysis of natural convection and entropy generation in a porous square enclosure using ECOP analysis: Effects of linear heating position and porosity

Year: 2026
Type: article
Abstract: Numerical simulations were performed for a heated square cavity under laminar natural convection at four Rayleigh numbers (Ra = 103, 104, 105, and 106) and three permeability levels (Da = 10-1, 10-3, and 10-5). The influence of five linear heating positions on the left wall (HS = 0, 0.25, 0.5, 0.75, and 1.0) was examined in detail. The impacts of these parameters on heat transfer, flow patterns, and entropy generation were analyzed and reported through streamlines (φ), isotherms (θ), heatline contours (Π), local and average Nusselt numbers (Nu), average entropy components (SHT, SFF, ST), average Bejan number (Be), and the ECOP number, which was used to identify the most favorable operating conditions. It was determined that increasing porosity reduces velocities and heat transfer, and that changes in porosity are more dominant than the Rayleigh number. As the Rayleigh number increased, the average Nusselt number also increased continuously, reaching its maximum when the heating center was positioned at the upper boundary (HS = 1). Analysis of the ECOP values showed that the highest performance was achieved at HS = 1, followed by HS = 0, confirming HS = 1 as the configuration associated with minimal irreversibility and maximum heat transfer. Conversely, the highest irreversibility occurred at HS = 0.25, while the lowest values appeared at HS = 0 and HS = 1, depending on the Rayleigh number. At low Darcy numbers, total entropy generation was found to be governed predominantly by the thermal component of entropy production. At elevated Rayleigh numbers, the influence of the heating position on ECOP became negligible.
DOI: 10.1016/j.csite.2026.107936
Author: Birol Şahin
Language: English
Open Access status: gold
Estimated APC paid: $1,620
OpenAlex ID: W7135029941
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Cites: 85
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