Entropy generation for an axisymmetric MHD flow under thermal non-equilibrium in porous micro duct using a modified lattice Boltzmann method

The present paper centered on a numerical investigation of irreversibility within a porous micro duct subjected to an external oriented magnetic field. At the wall, slip velocity and temperature jump are used as types of boundary conditions. The flow is described by Darcy-Brinkman-Forchheimer model. The Local Thermal Non Equilibrium (LTNE) is adopted including viscous dissipation effects into the energy equation of fluid phase. The study has been carried out for slip-flow regime for wide range of Knudsen numbers, 10(-3) <= Kn <= 10(-1). The obtained governing system equations are solved using the modified Lattice Boltzmann Method (LBM). Efforts are focused on identifying the influence of magnetic field on the entropy generation and Bejan number with a change of various parameters such as Knudsen, Eckert, Biot, Darcy numbers and thermal conductivity ratio. The obtained results show that the irreversibility and the contribution of heat transfer irreversibility and fluid flow irreversibility are strongly affected by the presence of magnetic field. (C) 2016 Elsevier B.V. All rights reserved.