Impact of Partial Filling of Metal Foams on Entropy Generation in a Vertical Channel

Abstract

This paper presents the analysis of entropy generation through metal foams filled in a vertical channel. Few reported research works reveals the importance of entropy generation through porous media completely filled in horizontal channels, hence this study is carried out with an intention to analyze the impact of partial filling of metal foams on thermal and frictional entropy generation in a vertical channel compared to completely filled metal foams. The numerical model consists of a heater which is inserted between two aluminum plates and is situated at the core of the channel. To augment the heat transfer from the plate aluminum metal foam of pore density 10 PPI (Pores per inch) with porosity 0.95 are located on the sideways of the plate. The numerical simulations for metal foam filling rates of 25%, 50%, 75%, and 100% are carried out for fluid inlet velocity ranging from 0.1 to 3 m/s. The flow-through metal foam is predicted with the help of Darcy Extended Forchheimer model while the heat transfer is projected by means of local thermal non-equilibrium (LTNE) model. For the purpose of validating the methodology adopted, the present work results are compared with the results available in the literature and noticed a good agreement between them. The entropy generation owing to both heat transfer and flow friction, and irreversibility in terms of Bejan number are presented and discussed. It is found that the total entropy generated owing to both heat transfer and pressure drop is less in 75% (H′ = 0.75 H) filling rate and it is about 25% with respect to completely filled channel.