International Journal of Thermofluids (May 2021)
Thermal analysis of flow in a porous flat tube in the presence of a nanofluid: Numerical approach
Abstract
Heat transfer enhancement is an important subject in heat exchangers research. An understanding of different shapes and designs of tubes and pipes means of improving heat extraction will have a direct effect on a new design for a heat exchanger. The present paper involved various investigations of thermal efficiency in flat tubes and regular pipes. The results revealed that a flat tube with an aspect ratio of 0.15 (Width/Height) exhibited enhanced heat extraction when compared to a circular pipe for the same cross section. The insertion of a porous material in the flat tube further improved the heat extraction, as seen by examining the thermal efficiency, known to be the ratio of the local Nusselt number to the fanning friction coefficient. Furthermore, the presence of a nanofluid in the flat tube flow led to an improvement in heat extraction depending on the concentration of the nanoparticle. A 5% enhancement was noticeable for a Reynolds number of 1000 with 1%vol Al2O3/water nanofluid for a flat tube. The enhancement increased to 12% in the presence of 2%vol Al2O3/water nanofluid. This enhancement was independent of the Reynolds number.
