Covalent-functionalized graphene nanoplatelets (CF-GNPs) inside a circular heated-pipe and the subsequent pressure decrease loss within a fully developed turbulent flow were discussed in this research. Four samples of nanofluids were prepared and investigated in the ranges of 0.025 wt.%, 0.05 wt.%, 0.075 wt.%, and 0.1 wt.%. Different tools such as field emission scanning electron microscopy (FE-SEM), ultraviolet-visible-spectrophotometer (UV-visible), energy-dispersive X-ray spectroscopy (EDX), zeta potential, and nanoparticle sizing were used for the data preparation. The thermophysical properties of the working fluids were experimentally determined using the testing conditions established via computational fluid dynamic (CFD) simulations that had been designed to solve governing equations involving distilled water (DW) and nanofluidic flows. The average error between the numerical solution and the Blasius formula was ~4.85%. Relative to the DW, the pressure dropped by 27.80% for 0.025 wt.%, 35.69% for 0.05 wt.%, 41.61% for 0.075 wt.%, and 47.04% for 0.1 wt.%. Meanwhile, the pumping power increased by 3.8% for 0.025 wt.%, 5.3% for 0.05 wt.%, 6.6% for 0.075%, and 7.8% for 0.1 wt.%. The research findings on the cost analysis demonstrated that the daily electric costs were USD 214, 350, 416, 482, and 558 for DW of 0.025 wt.%, 0.05 wt.%, 0.075 wt.%, and 0.1 wt.%, respectively.

Thermal and economic evaluation using covalent functionalized Graphene Nanoplatelets (CF-GNPs) were performed inside a heated-pipe under turbulent conditions. The current nanofluids were produced from CF-GNPs added and distilled water in different mass percentages such as 0.025,0.05,0.075 and 0.1wt.%. The thermal system was under the condition of fully-developed turbulent flow in the range of 6,401 ≤ Re ≤ 11,907 and heated up to 11,205 W/m2. The characterization and morphological properties were done through different examinations and techniques such as zeta potential, nanoparticle sizer, Field Emission Scanning Electron Microscopy (FE-SEM), and Field Emission Transmission Electron Microscope (FE-TEM). Moreover, the economic performance was evaluated to estimate the price-operation of the current thermal system. The heat exchanger size reduced by 16.10%, 21.92%, 25.37% and 29.35% for 0.025wt.%, 0.05wt.%, 0.075wt.% and 0.1wt.%, respectively. Furthermore, the required power for base fluid was 422W then reduced to 354W, 326W, 315W and 298W for 0.025wt.%, 0.05wt.%, 0.075wt.% and 0.1wt.%, respectively.

Graphene has piqued the interest of many researchers due to its superior mechanical, thermal, and physiochemical properties. Graphene nanoplatelets with covalently functionalized surfaces (CF-GNPs) were employed in turbulent-heated pipes to undertake thermal and economic studies. CF-GNPs and distilled water were used to make the current nanofluids at various mass percentages, such as 0.025, 0.05, 0.075%, and 0.1 wt.%. In the range of 6,401 Re 11,907, the thermal system was heated up to 11,205 W/m2 under fully developed turbulent flow conditions. Field emission scanning electron microscopy (FE-SEM), zeta potential, nanoparticle sizer, and field emission transmission electron microscopy (FE-TEM) were used to examine the morphological features and characterise the particles. In addition, the current thermal system’s economic performance was assessed to estimate its price-to-operate ratio. There was a 16.10% reduction in heat exchanger size for 0.025 weight percent, 0.05 weight percent, 0.075 weight percent, and 0.1 weight percent. In addition, the power needed for the base fluid was 422 W, which was then lowered to 354 W, 326 W, 315 W, and 298 W for 0.025 wt.%, 0.05 wt.%, 0.075 wt.%, and 0.1 wt.%, respectively.

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