https://doi.org/10.1140/epjp/s13360-024-04988-5
Regular Article
Heat transfer enhancement by natural convection in a partially porous annular space between two coaxial cylinders saturated by Cu–water nanofluid
Laboratory of Research in Physics and Engineering Sciences, Polydisciplinary faculty, Sultan Moulay Slimane university, 23000, Beni Mellal, Morocco
a
youness.foukharifpb@usms.ac.ma
Received:
12
October
2022
Accepted:
10
February
2024
Published online:
14
March
2024
The aim of this research is to investigate heat transfer by free convection in an annular, partially porous space between two coaxial cylinders with a permeable interface saturated by (Cu–water) nanofluid. The inner cylinder of the enclosure is kept at a constant hot temperature, while the outer is kept at a constant cold temperature. The base walls are impermeable and insulated. A finite difference-based vorticity-stream function approach is used to solve the nonlinear coupled conservation equations with prescribed boundary conditions, whereas the Successive Over Relaxation algorithm is used to solve the stream function equation. The obtained numerical results in terms of streamlines, isotherms, and heat transfer rate expressed by the Nusselt number are presented to demonstrate the effect of various control parameters, such as the Rayleigh number 
, Darcy number 
, porosity 
, nanoparticles concentration 
and the effective thermal conductivity. They showed that the increase in the Ra number and nanoparticle concentration causes an improvement in thermal energy transmission across the active wall. Also, the increase in the Da number makes the medium more permeable, which means more freedom for nanofluid to move. The results also show a significant effect of the porous layer thickness on the fluid flow pattern and the rate of thermal energy transport. Furthermore, this study demonstrates that there is a critical value of porosity for a given nanoparticle concentration for better heat transfer enhancement. Nonetheless, the purpose of this research could be to better understand the behavior of the nanofluid in this specific configuration, as well as to understand how other characteristics like porosity and porous layer thickness might influence heat transfer and fluid flow characteristics. This knowledge will be useful in a variety of industrial and technological applications where heat transfer efficiency is critical.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
