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.

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 Ultrasonic and thermophysical studies of ethylene glycol nanofluids containing TiO2 nanoparticles and their heat transfer enhancements

2020 ◽  
Author(s):  
Mohit Gupta ◽  
Devraj Singh ◽  
Shakti Pratap Singh ◽  
Ashish Mathur ◽  
Shikha Wadhwa ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Tio2 Nanoparticles ◽  
Ultrasonic Velocity ◽  
Base Fluid ◽  
Sol Gel ◽  
Interaction Force ◽  
Thermal Conductivity Enhancement ◽  
Conductivity Enhancement

In present investigation, TiO2 nanostructures were synthesized via simple sol-gel technique and characterized with XRD, SEM-EDX, HRTEM and UV-visible spectroscopy techniques. The temperature and concentration dependence of thermal conductivity enhancement and ultrasonic velocity have been explored in ethylene glycol (EG)-based TiO2 nanofluids. The obtained results showed 24% enhancement in thermal conductivity at higher temperature (80°C) of base fluid ethylene glycol by adding 1.0 wt.% of TiO2 nanoparticles. The behaviour of thermal conductivity enhancement and ultrasonic velocity with temperature in prepared nanofluids has been explained with help of existing phenomena. The increase the ultrasonic velocity in ethylene glycol with TiO2 nanoparticles shows that strong cohesive interaction force rises among the nanoparticles and base fluid. These results divulge that TiO2 nanoparticles can be considered for the applications of next-generation competent heat transfer in nanofluids.

scholarly journals A Comparison of Empirical Correlations of Viscosity and Thermal Conductivity of Water-Ethylene Glycol-Al2O3 Nanofluids

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1487
Author(s):  
Dorota Sawicka ◽  
Janusz T. Cieśliński ◽  
Slawomir Smolen
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Dynamic Viscosity ◽  
Base Fluid ◽  
Pure Water ◽  
Volume Ratio ◽  
Al2o3 Nanoparticles ◽  
Conductivity Enhancement ◽  
Viscosity Increase ◽  
New Generation

Because of their superb thermal conductivity, nanofluids are seen as new generation of cooling mediums in many engineering applications. It is well established that even a small amount of nanoparticles mixed with a base fluid may result in distinct thermal conductivity enhancement. On the other hand, addition of nanoparticles to the base fluid results in its substantial viscosity increase. Therefore, it is very difficult to evaluate the relative importance of viscosity and thermal conductivity of the nanofluid on convective heat transfer performance. In order to estimate such resultant impact properly, it is necessary to develop reliable correlation equations for predictions of these two thermophysical properties of nanofluids. In this paper, the thermal conductivity and dynamic viscosity of five fluids, i.e., pure water, ethylene glycol (EG) and three mixtures of water and EG with volume ratio of 40:60, 50:50 and 60:40 have been experimentally determined. The aforementioned fluids served as base fluids in nanofluids with Al2O3 nanoparticles at the concentration of 0.01%, 0.1% and 1% by weight. A set of 20 correlations for prediction of thermal conductivity and dynamic viscosity of base fluids and corresponding nanofluids has been developed. Moreover, present results have been confronted with literature data and predictions made by use of carefully selected recognized literature correlations.

scholarly journals Study the Effect of Gum Arabic and Triton X-100 on Stability and Thermal Conductivity of ZnO/ethylene glycol Nanofluids

2021 ◽  
Vol 72 (1) ◽  
pp. 18-24
Author(s):  
Noor Sabeeh Majeed ◽  
Hussein A. Alabdly ◽  
Hussam Nadum Abdalraheem Al Ani ◽  
Dumitru Pascu ◽  
Aurelia Cristina Nechifor
Keyword(s):  
Thermal Conductivity ◽  
Zinc Oxide ◽  
Zeta Potential ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
Thermal Conductivity Coefficient ◽  
Uv Spectroscopy ◽  
Gum Arabic ◽  
The Stability ◽  
Triton X

Stability of nanofluids is one of the most important factors to ensure the most benefit of the properties of nanoparticles. Zinc oxide was used in the research with concentration between (0.2-1) wt. % with ethylene glycol base fluid. The stability of ZnO nanofluid was enhanced by adding two types of surfactants Tx-100 and Gum Arabic with concentration of (0.1-0.5) vol. % to stabilize the ZnO nanoparticles in the base fluid. The results showed that the Gum Arabic surfactant led to more stable fluid than that of Tx-100; this was shown from zeta potential and UV spectroscopy measurements. The thermal conductivity coefficient was also measured, and the results showed that the thermal conductivity increased with adding surfactant than without using a stabilizer.

scholarly journals Interfacial Engineering of Graphene Nanosheets at MgO Particles for Thermal Conductivity Enhancement of Polymer Composites

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 798 ◽  
Author(s):  
Wu Pan ◽  
Miaomiao He ◽  
Li Zhang ◽  
Yi Hou ◽  
Chen Chen
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Polymer Composites ◽  
Graphene Nanosheets ◽  
High Surface ◽  
Precipitation Method ◽  
Conductivity Enhancement ◽  
Interfacial Engineering ◽  
The Matrix ◽  
Thermally Conducting

An important task in facilitating the development of thermally conducting graphene/polymer nanocomposites is to suppress the intrinsically strong intersheet π-π stacking of graphene, and thereby to improve the exfoliation and dispersion of graphene in the matrix. Here, a pre-programmed intercalation approach to realize the in situ growth of graphene nanosheets at the inorganic template is demonstrated. Specifically, microsized MgO granules with controlled geometrical size were synthesized using a precipitation method, allowing the simultaneous realization of high surface activity. In the presence of a carbon and nitrogen source, the MgO granules were ready to induce the formation of graphene nanosheets (G@MgO), which allowed for the creation of tenacious linkages between graphene and template. More importantly, the incorporation of G@MgO into polymer composites largely pushed up the thermal conductivity, climbing from 0.39 W/m∙K for pristine polyethylene to 8.64 W/m∙K for polyethylene/G@MgO (60/40). This was accompanied by the simultaneous promotion of mechanical properties (tensile strength of around 30 MPa until 40 wt % addition of G@MgO), in contrast to the noteworthy decline of tensile strength for MgO-filled composites with over 20 wt.% fillers.

scholarly journals Synthesis of hybrid nanofluid with two-step method

2018 ◽  
Vol 67 ◽  
pp. 03057 ◽  
Author(s):  
Wayan Nata Septiadi ◽  
Ida Ayu Nyoman Titin Trisnadewi ◽  
Nandy Putra ◽  
Iwan Setyawan
Keyword(s):  
Thermal Conductivity ◽  
Base Fluid ◽  
Volume Fraction ◽  
Heat Transfer Fluid ◽  
Hybrid Nanofluid ◽  
Test Results ◽  
Step Method ◽  
Fluid Mixture ◽  
High Level ◽  
Better Than

Nanofluid is a liquid fluid mixture with a nanometer-sized solid particle potentially applied as a heat transfer fluid because it is capable of producing a thermal conductivity better than a base fluid. However, nanofluids have a weakness that is a high level of agglomeration as the resulting conductivity increases. Therefore, in this study, the synthesis of two nanoparticles into the base fluid called hybrid nanofluids. This study aims to determine the effect of nanoparticle composition on the highest thermal conductivity value with the lowest agglomeration value. This research was conducted by dispersing Al2O3-TiO2 nanoparticles in water with volume fraction of 0.1%, 0.3%, 0.5%, 0.7% in the composition of Al2O3-TiO2 ratio of 75%:25%, 50%:50%, 25%:75%. The synthesis was performed with a magnetic stirrer for 30 minutes. The tests were carried out in three types: thermal conductivity testing with KD2, visual agglomeration observation and absorbance measurements using UV-Vis, wettability testing with HSVC tools and Image applications. The test results showed that the ratio composition ratio of 75% Al2O3-25% TiO2 with a volume fraction of 0.7% resulted in an increase in optimum thermal conductivity with the best wettability and the longest agglomeration level.

Thermal conductivity enhancement of nanofluids containing graphene nanosheets

2011 ◽  
Vol 110 (8) ◽  
pp. 084302 ◽  
Author(s):  
Soujit Sen Gupta ◽  
V. Manoj Siva ◽  
Sreenath Krishnan ◽  
T. S. Sreeprasad ◽  
Pawan K. Singh ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Graphene Nanosheets ◽  
Thermal Conductivity Enhancement ◽  
Conductivity Enhancement

Thermal Transport Properties of Nanofluids Containing Carbon Nanotubes

2008 ◽  
Author(s):  
Huaqing Xie ◽  
Lifei Chen ◽  
Yang Li ◽  
Wei Yu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Base Fluid ◽  
Volume Fraction ◽  
Thermal Conductivity Enhancement ◽  
Mechanochemical Reaction ◽  
Multiwalled Carbon ◽  
Conductivity Enhancement ◽  
Lower Viscosity ◽  
Potential Applications

Multiwalled carbon nanotubes (CNTs) have been treated by using a mechanochemical reaction method to enhance their dispersibility for producing CNT nanofluids. The thermal conductivity was measured by a short hot wire technique and the viscosity was measured by a rotary viscometer. The thermal conductivity enhancement reaches up to 17.5% at a volume fraction of 0.01 for an ethylene glycol based nanofluid. Temperature variation was shown to have no obvious effects on the thermal conductivity enhancement for the as prepared nanofluids. With an increase in the thermal conductivity of the base fluid, the thermal conductivity enhancement of a nanofluid decreases. At low volume fractions (<0.4 Vol%), nanofluids have lower viscosity than the corresponding base fluid due to lubricative effect of nanoparticles. When the volume fraction is higher than 0.4 Vol%, the viscosity increases with nanoparticle loadings. The prepared nanofluids, with no contamination to medium, good fluidity, stability, and high thermal conductivity, would have potential applications as coolants in advanced thermal systems.

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