Covalently functionalized pentaethylene glycol-thermally treated graphene towards enhanced thermophysical and heat transfer characteristics

• Main Authors: Alawi, Omer A., Mallah, A. R., Kazi, S. N.
• Format: Article
• Published: Springer Science and Business Media B.V 2020
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://eprints.um.edu.my/36773/
• Institution: Universiti Malaya

The current study outlined the use of synthesized, covalently functionalized pentaethylene glycol-thermally treated graphene (PEG-TGr). Miscible PEG was decorated in order to achieve a long-stable aqueous colloidal dispersion. The experimentations were performed using the Reynolds number range of 6401-11,907, constant wall heat flux of 11,205 W/m(2), and mass fraction of 0.025, 0.05, 0.075, and 0.1%. The effective thermophysical characteristics, heat and momentum transfer for fully developed turbulent flow patterns of PEG-TGr nanofluids over a square heated pipe were examined. Performance index, performance evaluation criterion, and pumping power were assessed to evaluate the performance of nanofluids. An augmentation in thermal conductivity of PEG-TGr was observed in 29.74% in comparison with the base fluid. The heat transfer coefficient enhancement of PEG-TGr was about 41.18% with respect to distilled water data. Nonlinear regression correlations were experimentally developed to calculate the thermal conductivity, dynamic viscosity, Nusselt number, and friction number. It seems that PEG-TGr nanofluids perform as working fluids for heat transfer purposes and offer great alternative options to standard operating fluids inside the thermal fluid devices.