*Article* **Thermal and Hydraulic Performances of Carbon and Metallic Oxides-Based Nanomaterials**

**Haitham Abdulmohsin Afan <sup>1</sup> , Mohammed Suleman Aldlemy 2,3 , Ali M. Ahmed <sup>4</sup> , Ali H. Jawad <sup>5</sup> , Maryam H. Naser <sup>6</sup> , Raad Z. Homod <sup>7</sup> , Zainab Haider Mussa <sup>8</sup> , Adnan Hashim Abdulkadhim <sup>9</sup> , Miklas Scholz 10,11,12,13,\* and Zaher Mundher Yaseen 14,15,16,\***


**Abstract:** For companies, notably in the realms of energy and power supply, the essential requirement for highly efficient thermal transport solutions has become a serious concern. Current research highlighted the use of metallic oxides and carbon-based nanofluids as heat transfer fluids. This work examined two carbon forms (PEG@GNPs & PEG@TGr) and two types of metallic oxides (Al2O<sup>3</sup> & SiO<sup>2</sup> ) in a square heated pipe in the mass fraction of 0.1 wt.%. Laboratory conditions were as follows: <sup>6401</sup> <sup>≤</sup> Re <sup>≤</sup> 11,907 and wall heat flux = 11,205 W/m<sup>2</sup> . The effective thermal–physical and heat transfer properties were assessed for fully developed turbulent fluid flow at 20–60 ◦C. The thermal and hydraulic performances of nanofluids were rated in terms of pumping power, performance index (PI), and performance evaluation criteria (PEC). The heat transfer coefficients of the nanofluids improved the most: PEG@GNPs = 44.4%, PEG@TGr = 41.2%, Al2O<sup>3</sup> = 22.5%, and SiO<sup>2</sup> = 24%. Meanwhile, the highest augmentation in the Nu of the nanofluids was as follows: PEG@GNPs = 35%, PEG@TGr = 30.1%, Al2O<sup>3</sup> = 20.6%, and SiO<sup>2</sup> = 21.9%. The pressure loss and friction factor increased the highest, by 20.8–23.7% and 3.57–3.85%, respectively. In the end, the general performance of nanofluids has shown that they would be a good alternative to the traditional working fluids in heat transfer requests.

**Citation:** Afan, H.A.; Aldlemy, M.S.; Ahmed, A.M.; Jawad, A.H.; Naser, M.H.; Homod, R.Z.; Mussa, Z.H.; Abdulkadhim, A.H.; Scholz, M.; Yaseen, Z.M. Thermal and Hydraulic Performances of Carbon and Metallic Oxides-Based Nanomaterials. *Nanomaterials* **2022**, *12*, 1545. https:// doi.org/10.3390/nano12091545

Academic Editor: S M Sohel Murshed

Received: 30 March 2022 Accepted: 24 April 2022 Published: 3 May 2022

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**Keywords:** carbon nanostructures; metallic oxides; thermophysical properties; convective heat transfer; turbulent flow
