| Summary: | Abstract: This paper investigates entropy generation due to forced convection in a porous medium sandwiched between two parallel plates one of them being subjected to a uniform heat flux and the other one insulated. Our results showed that viscous dissipation will affect the entropy generation rate at the centerline of the channel since viscous dissipation is a quadratic function of velocity [1-3]. Neglecting the Darcy dissipation term in comparison with the terms added by Al-Hadrami et al. [4], will lead to the misunderstanding that fluid friction has no effect on the entropy generation rate at the tube centerline where the velocity derivative vanishes due to symmetry. Though the term added by [4] is O(Da) compared to the Darcy term one should not drop it unless the clear flow solution is sought [5-7]. Moreover, as stated by Nield [1], one should not use just the term involving velocity derivatives, as some authors have done in the past, for example [8-11]. Though in this paper the viscous dissipation effects in the energy equation are neglected, we have take them into account when it came to the entropy generation analysis.
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