The influence of hybrid nanofluids on the performances of elliptical tube: Recent research and numerical study

This paper is divided in two parts: first part summarizes most important research on elliptical tubes using conventional fluids and nanofluids, and in second part is numerical investigate the influence of MgO-MWCNT/ethylene glycol hybrid nanofluids on performances of elliptical tube. The numerical analysis was assumed as steady, three-dimensional and laminar flow. The analyses were performed for two inlet temperature, 313 K and 323 K, Reynolds number within the range 50-1000, and volume concentrations of hybrid nanoparticles in the range of 0-0.4%. The results showed an enhancement in heat transfer coefficients for all considered volume concentrations of hybrid nanoparticles, except the volume concentration of 0.1% and inlet temperature of 313 K. The highest increase in heat transfer coefficient was noticed for the MgO-MWCNT hybrid nanoparticles at a 0.4% volume concentration. Moreover, the high viscosity of 0.4% concentration of hybrid nanoparticles determined a high pressure drop highlighted in the pumping power. Additional, a detailed entropy analysis was conducted in the current study. Finally, experimental and numerical studies are needed to understand the behavior of hybrid nanofluids in thermal applications. (C) 2018 Elsevier Ltd. All rights reserved.