Entropy generation in a rectangular packed duct with wall heat flux
This paper studies the entropy generation due to heat transfer and friction for fully developed forced convection flow in a large rectangular duct, packed with spherical particles, with constant heat fluxes applied to both the top (heated) and bottom (cooled) wall. An approximate analytical expression for the velocity profile developed for packed bed with \(H/d_p>5\) (\(H\) is the depth of duct, and \(d_p\) is the diameter of packing) is used together with the energy equation for fully developed flow to calculate the non-isothermal temperature profiles along the flow passage. The effects of wall region \((H/d_p)\) and thermal boundary conditions on the entropy generation are displayed in figures in a qualitative and quantitative manner. It is found that the velocity distortion near the walls destroys the uniformity in the entropy generation and the irreversibility of distributions in the packed bed. The distortions in the wall regions are larger for higher values of \(H/d_p\). This is in agreement with the results from the literature.
scientific article; zbMATH DE number 1436804