Numerical analysis of a helically corrugated tube using a novel combination of W/EG-based non-Newtonian hybrid nanofluid

Abstract

In this study, the second law analysis of a non-Newtonian hybrid TiO2-SiO2 nanofluid based on water/ethylene glycol has been carried out. The influence of the corrugation-height ratio (e/dh) and volume fraction (φ) on the rates of entropy creation and exergy destruction are investigated using a helically corrugated tube. The model is simulated using ANSYS FLUENT 19.0 with the corrugated wall kept at a constant heat flux of 25 kW/m2 and a range of hybrid nanofluid volume flow rates from 15 to 25 lpm. As the corrugation height and particle volume percentage increases, the HCT's rates of entropy generation and exergy destruction decrease. Additionally, as the volume flow rate of the hybrid nanofluid increases within the abovementioned range, the Bejan number and entropy generation number also decrease. For volume fraction of 5%, the Bejan number decreases to 0.873 at 25 lpm. The total irreversibility is reduced by adding corrugation and employing hybrid nanofluids. Also, working with the combination of corrugation and hybrid nanofluid leads to a notable increase in exergetic efficiency, reaching a maximum value of 82.8%.