DOI: 10.1615/ICHMT.2004.IntThermSciSemin
ISBN Print: 978-9-61913-930-1
Thermodynamic Analysis in a Partly Porous Annular Heat Exchanger
RESUMO
The entropy generation due to heat transfer and to fluid friction has been analyzed for an annular heat exchanger partly or fully filled with a porous medium. The porous medium is attached to the inner cylinder, which is heated with a hot fluid while the outer cylinder is adiabatic. The objective of this study is to find the best conditions in order to minimize pressure drop, to enhance heat transfer and to reduce entropy generation. The effect of several parameters such as the thickness of the porous substrate, its permeability and its thermal conductivity are investigated. The numerical predictions show the existence of a critical thickness which depends on inlet conditions and the permeability of the porous layer. Beyond this thickness, the entropy generation decreases. Moreover, an increase in the effective thermal conductivity of the porous medium seems to be thermodynamically more advantageous.