Second Law Analysis Through a Porous Poiseuille–Benard Channel Flow

Abstract

This paper proposes a numerical analysis of entropy generation during mixed convection inside a porous Poiseuille–Benard channel flow, where the Darcy–Brinkman model is used. Irreversibilities due to heat transfer and viscous dissipation have been derived, and then calculated by numerically solving mass, momentum, and energy conservation equations, by using a control volume finite element method (CVFEM). For a fixed value of the thermal Rayleigh (Ra = 104) and the modified Brinkman (Br* = 10−3) numbers, transient entropy generation exhibits a periodic behavior for the medium porosity ε ≥ 0.2, which is described by the onset of thermoconvective cells inside the porous channel. Highest irreversibility is obtained at ε = 0.5. More details about the effects of the Darcy, the Rayleigh, and the modified Brinkman numbers on entropy generation and heat transfer are discussed and graphically presented.

A computational analysis of heat transport irreversibility phenomenon in a magnetized porous channel

“…The thermo-convective cells move in the direction of the main flow as cylinders that turn without translation on walls. Similar results with good agreement with these results are reported in Tayari et al (2015).…”

“…Thus, the flow is characterized by the presence of thermo-convective cells near the bottom and the top walls that reminds us the PB flow configuration. This means that the PB configuration still exists even in porous channel under magnetic field with relatively high porosity and permeability, and for relatively small Hartman numbers (Figures 4a, b and c) (Tayari et al, 2015).…”