Second Law Analysis Through a Porous Poiseuille-Benard Channel Flow

摘要

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 = 10~4) 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 irre-versibility 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.