8 - Entropy generation in porous media

Abstract

The chapter reviews entropy generation for porous media, and investigates recent studies related to entropy generation for porous cavities and channels for different boundary conditions and physical situations. Using a variety of numerical, experimental, and analytical methods, results are published for many engineering applications regarding forced and free convection in porous channels and cavities that are in geometrically simple enclosures, e.g. rectangular cavities, cylindrical containers, and complex geometries. This significant interest in entropy generation is motivated by its importance in many natural and industrial applications. Recently, research on entropy generation minimization using the second law of thermodynamics is studied for many different situations. The utilization of the second law of thermodynamics in thermal design decision is developed and applied for porous media. For this reason, these lines of inquiry are largely motivated by a desire to obtain an in-depth understanding of the relevant physics underlying this phenomena. Understanding the nature of irreversibility and how to minimize them in practice is essential for an engineering thermodynamist. Contemporary engineering thermodynamics uses the rate of entropy generation as a parameter to quantify the significance of these irreversibilities. The local values of entropy generation due to viscous and thermal effects can be mapped to detect, by inspection, the key areas that require a design modification. This emerging technology has a meaningful potential for improving thermal system designs.