Investigation into the effect of twisted tape on the thermo-hydraulic performance and entropy generation of turbulent flow of mono and hybrid magnetic nanofluids inside a parabolic solar collector absorber tube by applying two-phase analysis

Abstract

This research study examines the impact of applying a twisted tape on thermo-hydraulic performance as well as entropy generation related to the turbulent flow of mono and hybrid magnetic nanofluids inside a parabolic solar collector (PSC) absorber tube. In this study, two-phase water/multi-walled carbon nanotubes (MWCNTs) nanofluid and two-phase water/MWCNT-iron oxide nanofluid having the 1% volume fraction (VF) are applied as the working fluid. To model two-phase flow, the mixture model standard k-ε turbulence model and QUICK algorithm are utilized. This research study is implemented for diverse Reynolds numbers of 6000 to 24000 and some twisted tape's pitch ratios including 0.25, 0.50, and 0.75. In addition, the standard k-ε turbulence model is then applied for modeling the turbulent flow. The obtained results obtained by the numerical study demonstrate that using the twisted tape in solar collectors could improve thermo-hydraulic performance in comparison to the solar collector with no particular twisted tape. Also, the considered HT related to the collector having twisted tape is more than that without twisted tape in all cases, i.e., thermo-hydraulic performance coefficient is always greater than 1. The results reveal that using magnetic hybrid nanofluid leads to better thermal performance than mono nanofluid. Finally, the entropy generation is reduced with the Reynolds number as well as the pitch ratio of the twisted tape. The highest value in PEC surge was about 27% owing to using of magnetic hybrid nanofluid, while for simple nanofluid, it was 22%. According to this case, the use of magnetic hybrid nanofluid is recommended.