Thermohydraulic analysis of covalent and noncovalent functionalized graphene nanoplatelets in circular tube fitted with turbulators

• Published in: Scientific reports
• Main Author: Tao H.; Alawi O.A.; Hussein O.A.; Ahmed W.; Abdelrazek A.H.; Homod R.Z.; Eltaweel M.; Falah M.W.; Al-Ansari N.; Yaseen Z.M.
• Format: Article
• Language: English
• Published: NLM (Medline) 2022
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85140345460&doi=10.1038%2fs41598-022-22315-9&partnerID=40&md5=958e7fefd10286288f8f3058a3e059e9

Covalent and non-covalent nanofluids were tested inside a circular tube fitted with twisted tape inserts with 45° and 90° helix angles. Reynolds number was 7000 ≤ Re ≤ 17,000, and thermophysical properties were assessed at 308 K. The physical model was solved numerically via a two-equation eddy-viscosity model (SST k-omega turbulence). GNPs-SDBS@DW and GNPs-COOH@DW nanofluids with concentrations (0.025 wt.%, 0.05 wt.% and 0.1 wt.%) were considered in this study. The twisted pipes' walls were heated under a constant temperature of 330 K. The current study considered six parameters: outlet temperature, heat transfer coefficient, average Nusselt number, friction factor, pressure loss, and performance evaluation criterion. In both cases (45° and 90° helix angles), GNPs-SDBS@DW nanofluids presented higher thermohydraulic performance than GNPs-COOH@DW and increased by increasing the mass fractions such as 1.17 for 0.025 wt.%, 1.19 for 0.05 wt.% and 1.26 for 0.1 wt.%. Meanwhile, in both cases (45° and 90° helix angles), the value of thermohydraulic performance using GNPs-COOH@DW was 1.02 for 0.025 wt.%, 1.05 for 0.05 wt.% and 1.02 for 0.1 wt.%. © 2022. The Author(s).