Comparative Study of Carbon Nanosphere and Carbon Nanopowder on Viscosity and Thermal Conductivity of Nanofluids

Abstract

A comparative research on stability, viscosity (µ), and thermal conductivity (k) of carbon nanosphere (CNS) and carbon nanopowder (CNP) nanofluids was performed. CNS was synthesized by the hydrothermal method, while CNP was provided by the manufacturer. Stable nanofluids at high concentrations 0.5, 1.0, and 1.5 vol% were prepared successfully. The properties of CNS and CNP nanoparticles were analyzed with Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), specific surface area (SBET), X-ray powder diffraction (XRD), thermogravimetry/differential thermal analysis (TG/DTA), and energy dispersive X-ray analysis (EDX). The CNP nanofluids have the highest k enhancement of 10.61% for 1.5 vol% concentration compared to the base fluid, while the CNS does not make the thermal conductivity of nanofluids (knf) significantly higher. The studied nanofluids were Newtonian. The relative µ of CNS and CNP nanofluids was 1.04 and 1.07 at 0.5 vol% concentration and 30 °C. These results can be explained by the different sizes and crystallinity of the used nanoparticles.

Thermal Conductivity Enhancement of Atomic Layer Deposition Surface-Modified Carbon Nanosphere and Carbon Nanopowder Nanofluids

“…The ALD-CNP nanoparticles are more uniform and have a smoothed surface compared to the original CNP. The average particle size of the CNS is 498 nm, as obtained in previous research by treatment of SEM images with respect to the original nanoparticles, whereas the CNP has an average diameter of 100 nm, according to the manufacturer [25]. In Figure 1c,d, the surface layer of the TiO 2 can be observed with a thickness of 3 nm.…”

“…In our previous research, the highest relative viscosity increase was 9.31 % for the CNS and 9.56 % for the CNP nanofluids. In comparison, the ALD-CNS nanofluids experienced a drastic increase of 37.5 %, whereas the ALD-CNP nanofluids exhibited a maximal viscosity increase of just 15.9 % [25]. In Figure 7, the dynamic viscosity is represented at different temperatures.…”

“…Stable nanofluids were prepared from the original carbon nanospheres with the use of a 5:1 deionised water (DI)/ethanol base fluid. The original carbon nanopowder was stable in a 1:1 ethylene-glycol/DI mixture with surfactants [25]. After ALD, it was possible to avoid the use of surfactants.…”

“…In this paper, novel ALD-modified carbon-nanostructure-based nanofluids were studied with water/ethanol and ethylene-glycol base fluids, following previous research regarding the original carbon nanosphere (CNS) and carbon nanopowder (CNP) materials [25]. Several nanometres of TiO 2 was grown on the surface of the nanoparticles according to the ALD process.…”

Thermophysical Properties of Nanofluid in Two-Phase Fluid Flow through a Porous Rectangular Medium for Enhanced Oil Recovery

“…Fluids containing suspended nanoparticles have the potential to significantly enhance oil recovery procedures and increase oil extraction from reservoirs [ 7 , 8 , 9 ]. The incorporation of nanoparticles into the base fluid would affect the heat transport [ 10 , 11 , 12 , 13 ], the fluid viscosity [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ], the thermal conductivity [ 21 , 22 , 23 ], and the rheological conductivity [ 22 , 24 , 25 ]. This approach is regarded as one of the alternate methods for locating new hydrocarbon reserves [ 26 ].…”