IRREVERSIBILITY ANALYSIS IN MIXED CONVECTION FLOW IN A POROUS CHANNEL WITH VISCOUS DISSIPATION

Various constraints acting on a flow, such as heat transfer, viscous fluid friction, and chemical reaction, are sources of irreversibility and therefore responsible for entropy generation. In this paper, the mixed convection with viscous dissipation effect in an inclined channel filled with a saturated porous medium is investigated numerically, by using the Darcy-Brinkman model. The Navier-Stokes and energy equations are solved by classic Boussinesq approximation. First, the effect of the Darcy number on the total entropy generation in the horizontal porous channel is investigated in the absence and in the presence of viscous the dissipation term. In this case, the Prandtl number and the Brinkman number are considered as parameters. The contribution of the different irreversibility causes on the total entropy generation is analyzed by the investigation of the Bejan number versus Darcy number, with the Prandtl number as parameter. Next, the fluctuations of the transient total entropy generation were investigated when the inclination angle varies from 0 deg to 180 deg. Moreover, the effect of the channel inclination angle on both the entropy generation and the Bejan number was investigated. It was found that the total entropy generation is maximum at inclination angle close to 70 deg and minimum at 0 deg and 180 deg.