The Preparation and Thermal Conductivities Enhacement of Nanofluids Containing Graphene Oxide Nanosheets

2010 ◽  
Author(s):  
Wei Yu ◽  
Huaqing Xie ◽  
Lifei Chen ◽  
Yang Li ◽  
Dehui Li
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Ethylene Glycol ◽  
High Stability ◽  
Hot Wire ◽  
Graphene Oxide Nanosheets ◽  
Metallic Oxide ◽  
Conductivity Enhancement ◽  
Hydrophilic Surfaces ◽  
Thermal Conductivities

The work presents a method to prepare stable nanofluids containing graphene oxide nanosheets (GO-EG nanofluid). The hydrophilic surfaces let graphene oxide nanosheets have good compatibility with ethylene glycol. The thermal conductivity of the nanofluids was measured by a short hot wire technique, and the result shows that the thermal conductivity of GO-EG nanofluids is almost constant within 7 days, and it reflects the high stability of GO-EG nanofluids. The thermal conductivity enhancement ratios of GO-EG nanofluids were almost constant with tested temperatures vary. GO-EG nanofluids have substantially higher thermal conductivities than the base fluids. When the loading is 5.0 vol.%, the enhancement ratios is up to 61%, much larger than those of metallic oxide. For 1.0 vol.% GO-EG nanofluid, the enhancement ratios is 10.5%, less than those of CNT with the same loading. The reason may be due to the defects, caused by the treatment with strong Oxidants. In our opinion, heat transport in the GO nanosheet is one of the major contributions to the increase of the effective thermal conductivity of nanofluids.

The Thermal Transport Properties of Ethylene Glycol Based MGO Nanofluids

2009 ◽  
Author(s):  
Wei Yu ◽  
Hua-Qing Xie ◽  
Yang Li ◽  
Li-Fei Chen
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Transport Properties ◽  
Volume Fraction ◽  
Metallic Oxide ◽  
Mgo Nanoparticles ◽  
Conductivity Enhancement ◽  
Classical Models ◽  
Constant Viscosity ◽  
Solid Liquid

Ethylene glycol based nanofluids containing MgO nanoparticles (MgO-EG) were prepared, and the transport properties including thermal conductivity and viscosity were measured. The results show that the thermal conductivity of MgO-EG nanofluid depends strongly on particle concentration, and it increases nonlinearly with the volume fraction of nanoparticles. The thermal conductivity of MgO-EG nanofluids is larger than that of nanofluids containing the same volume fraction of TiO2, ZnO, Al2O3 and SiO2, maybe due to its lowest viscosity among the tested metallic oxide nanofluids. Thermal conductivity enhancement of MgO-EG nanofluids appears weak dependence on temperature from 10 to 60°C, and the enhanced ratios are almost constant. Viscosity measurements show that MgO-EG nanofluids demonstrate Newtonian behavior, and the viscosity significantly decreases with temperature. The thermal conductivity and viscosity increments of nanofluids are higher than those of the existing classical models for the solid-liquid mixture.

Effect of Volume Fraction and Temperature on Thermal Conductivity of SiO2 Nanofluids

2011 ◽  
Vol 306-307 ◽  
pp. 1178-1181 ◽  
Author(s):  
Bao Jie Zhu ◽  
Wei Lin Zhao ◽  
Dong Dong Li ◽  
Jin Kai Li
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Volume Fraction ◽  
Experimental Results ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Transient Hot Wire Method ◽  
Wire Method ◽  
Thermal Conductivities

Thermal conductivities of two kinds of nanofluids (SiO2-water and SiO2-ethylene glycol) were measured by transient hot-wire method at different volume fraction and temperature. Influences of volume fraction of particles and temperature on thermal conductivities of nanofluids were analyzed. The Experimental results show that thermal conductivities of nanofluids are higher than those of base fluids, and increase with the increase of volume fraction and temperature. When approximately 0.5% volume fraction of SiO2nanoparticles are added into water and ethylene glycol at the temperature 50°C, the thermal conductivities are enhanced 46.2% and 62.8% respectively.

Design of a Steady-State, Parallel-Plate Thermal Conductivity Apparatus for Nanofluids and Comparative Measurements With Transient HWTC Apparatus

2010 ◽  
Author(s):  
Milivoje M. Kostic ◽  
Casey J. Walleck
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Parallel Plate ◽  
Measurement Method ◽  
Mixture Theory ◽  
Hot Wire ◽  
Electro Magnetic ◽  
Magnetic Phenomena ◽  
Thermal Conductivities

A steady-state, parallel-plate thermal conductivity (PPTC) apparatus has been developed and used for comparative measurements of complex POLY-nanofluids, in order to compare results with the corresponding measurements using the transient, hotwire thermal conductivity (HWTC) apparatus. The related measurements in the literature, mostly with HWTC method, have been inconsistent and with measured thermal conductivities far beyond prediction using the well-known mixture theory. The objective was to check out if existing and well-established HWTC method might have some unknown issues while measuring TC of complex nano-mixture suspensions, like electro-magnetic phenomena, undetectable hot-wire vibrations, and others. These initial and limited measurements have shown considerable difference between the two methods, where the TC enhancements measured with PPTC apparatus were about three times smaller than with HWTC apparatus, the former data being much closer to the mixture theory prediction. However, the influence of measurement method is not conclusive since it has been observed that the complex nano-mixture suspensions were very unstable during the lengthy steady-state measurements as compared to rather quick transient HWTC method. The nanofluid suspension instability might be the main reason for very inconsistent results in the literature. It is necessary to expend investigation with more stable nano-mixture suspensions.

THE THERMAL CONDUCTIVITY OF DEUTERIUM

1935 ◽  
Vol 12 (3) ◽  
pp. 372-376 ◽  
Author(s):  
A. B. Van Cleave ◽  
O. Maass
Keyword(s):  
Thermal Conductivity ◽  
Hydrogen Molecule ◽  
Hydrogen Isotopes ◽  
Hot Wire ◽  
Wire Method ◽  
Deuterium Molecule ◽  
Thermal Conductivities

The thermal conductivities of deuterium and some mixtures of deuterium and hydrogen have been measured by a relative, "hot wire" method. The results are consistent with the authors' original conclusion that the deuterium molecule has the same molecular diameter as the hydrogen molecule. It follows also that the molecular heats of the hydrogen isotopes are the same.

Analysis of nanofluids as a means of thermal conductivity enhancement in heavy machineries

2014 ◽  
Vol 66 (2) ◽  
pp. 238-243 ◽  
Author(s):  
Ayush Jain ◽  
Imbesat Hassan Rizvi ◽  
Subrata Kumar Ghosh ◽  
P.S. Mukherjee
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
High Concentration ◽  
Content Type ◽  
Conductivity Enhancement ◽  
Heavy Machinery ◽  
Heat Transfer Fluids ◽  
Experimental Findings

Purpose – Nanofluids exhibit enhanced heat transfer characteristics and are expected to be the future heat transfer fluids particularly the lubricants and transmission fluids used in heavy machinery. For studying the heat transfer behaviour of the nanofluids, precise values of their thermal conductivity are required. For predicting the correct value of thermal conductivity of a nanofluid, mathematical models are necessary. In this paper, the effective thermal conductivity of various nanofluids has been reported by using both experimental and mathematical modelling. The paper aims to discuss these issues. Design/methodology/approach – Hamilton and Crosser equation was used for predicting the thermal conductivities of nanofluids, and the obtained values were compared with the experimental findings. Nanofluid studied in this paper are Al2O3 in base fluid water, Al2O3 in base fluid ethylene glycol, CuO in base fluid water, CuO in base fluid ethylene glycol, TiO2 in base fluid ethylene glycol. In addition, studies have been made on nanofluids with CuO and Al2O3 in base fluid SAE 30 particularly for heavy machinery applications. Findings – The study shows that increase in thermal conductivity of the nanofluid with particle concentration is in good agreement with that predicted by Hamilton and Crosser at typical lower concentrations. Research limitations/implications – It has been observed that deviation between experimental and theoretical results increases as the volume concentration of nanoparticles increases. Therefore, the mathematical model cannot be used for predicting thermal conductivity at high concentration values. Originality/value – Studies on nanoparticles with a standard mineral oil as base fluid have not been considered extensively as per the previous literatures available.

scholarly journals Thermal conductivity enhancement in gold decorated graphene nanosheets in ethylene glycol based nanofluid

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
M. C. Mbambo ◽  
M. J. Madito ◽  
T. Khamliche ◽  
C. B. Mtshali ◽  
Z. M. Khumalo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
Graphene Nanosheets ◽  
Synthesis Method ◽  
Particle Diameter ◽  
Laser Wavelength ◽  
Hybrid Nanofluid ◽  
Average Particle ◽  
Conductivity Enhancement

Abstract We report on the synthesis and thermal conductivity of gold nanoparticles (AuNPs) decorated graphene nanosheets (GNs) based nanofluids. The GNs-AuNPs nanocomposites were synthesised using a nanosecond pulsed Nd:YAG laser (wavelength = 1,064 nm) to ablate graphite target followed by Au in ethylene glycol (EG) base fluid to obtain GNs-AuNPs/EG hybrid nanofluid. The characterization of the as-synthesised GNs-AuNPs/EG hybrid nanofluid confirmed a sheet-like structure of GNs decorated with crystalline AuNPs with an average particle diameter of 6.3 nm. Moreover, the AuNPs appear smaller in the presence of GNs which shows the advantage of ablating AuNPs in GNs/EG. The thermal conductivity analysis in the temperature range 25–45 °C showed that GNs-AuNPs/EG hybrid nanofluid exhibits an enhanced thermal conductivity of 0.41 W/mK compared to GNs/EG (0.35 W/mK) and AuNPs/EG (0.39 W/mK) nanofluids, and EG base fluid (0.33 W/mK). GNs-AuNPs/EG hybrid nanofluid displays superior enhancement in thermal conductivity of up to 26% and this is due to the synergistic effect between AuNPs and graphene sheets which have inherent high thermal conductivities. GNs-AgNPs/EG hybrid nanofluid has the potential to impact on enhanced heat transfer technological applications. Also, this work presents a green synthesis method to produce graphene-metal nanocomposites for various applications.

Thermal Conductivity Measurement of Hydrogen at High Pressure and High Temperature

2011 ◽  
Author(s):  
Koichi Kimura ◽  
Shogo Moroe ◽  
Peter Woodfield ◽  
Jun Fukai ◽  
Kan’ei Shinzato ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Pressure Range ◽  
Conductivity Measurement ◽  
Good Reproducibility ◽  
Hot Wire ◽  
Wire Method ◽  
Transient Short Hot Wire ◽  
Thermal Diffusivities ◽  
Thermal Conductivities

The thermal conductivities and thermal diffusivities of hydrogen were measured with a transient short hot wire method for temperature range up to 300 °C and pressure range up to 100MPa. The measured thermal conductivities showed good reproducibility and agreed with the existing values within a deviation of ±2%.

Thermal Conductivity Enhancement of Ethylene Glycol-Based Suspensions in the Presence of Silver Nanoparticles of Various Shapes

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Xin Fang ◽  
Qing Ding ◽  
Li-Wu Fan ◽  
Zi-Tao Yu ◽  
Xu Xu ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
The Other ◽  
Thermal Conductivity Enhancement ◽  
Shape Effect ◽  
Conductivity Enhancement ◽  
Shape Dependence ◽  
Aspect Ratios ◽  
Relative Enhancement ◽  
Particle Shape Effect

In this technical brief, the effect of adding silver (Ag) nanoparticles of various shapes on the thermal conductivity enhancement of ethylene glycol (EG)-based suspensions was investigated experimentally. These included Ag nanospheres (Ag NSs), Ag nanowires (Ag NWs), and Ag nanoflakes (Ag NFs). Measurements of the thermal conductivity of the suspensions were performed from 10 to 30 °C at an increment of 5 °C. It was shown that the thermal conductivity of the EG-based suspensions increases with raising the temperature. The Ag NWs of a high aspect ratio (∼500) caused greatest relative enhancement up to 15.6% at the highest loading of nearly 0.1 vol. %, whereas the other two shapes of nanoparticles, Ag NSs and Ag NFs with much smaller aspect ratios, only led to enhancements up to 5%. The formation of a network of Ag NWs that facilitates heat conduction was likely responsible for their better performance. The relative enhancement was also predicted by the Hamilton-Crosser model that takes the particle shape effect into consideration. It was shown that the predictions far underestimate the thermal conductivity enhancements but are qualitatively consistent with their shape dependence. As a penalty, however, the presence of Ag NWs was shown to give rise to significant increase in the viscosity of the EG-based suspensions.

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