Performing SiO2-MWCNT/water hybrid nanofluid with differently shaped nanoparticles to enhance first- and second-law features of flow by considering a two-phase approach

Abstract

AbstractThe utilization of hybrid nanofluids has gained essential consideration in thermal engineering. Changes in the thermal characteristics of the base fluid are responsible for the improved thermal conductivity brought about by hybrid nanoparticles and their shapes. For this goal, in this paper, the two-phase 60%:40% SiO2-MWCNT/water hybrid nanofluid flow at the Reynolds number range of 3000–10,000 in a square duct is investigated concerning first- and second-law analysis. The turbulent flow regime is modeled using the RNG k–ε turbulence approximation. The hybrid nanofluid is modeled via a mixed model. The parameters used in this study are three different nanoparticle shapes (cylindrical, spherical, and platelet) and nanoparticle volume fractions (0.2%, 0.6%, and 1.0%). The distributions of the Nusselt number, friction factor, entropy generation, exergy destruction, exergy efficiency, temperature, and velocity contours are investigated in detail for the above parameters. It is found that the most significant increases in PEC are seen in hybrid nanofluids with the PC and PP shapes, at 2.27 and 3.24%, respectively. It has been shown that the exergy destruction of hybrid nanofluids with the second nanoparticle forms C and P is 43.90% and 58.74% more than that of a S one when PS-, PC-, and PP-shaped nanoparticles are utilized. The hybrid nanofluid with the PS shape has the highest exergy efficiency, whereas the SP-shaped nanofluid has the lowest.