scholarly journals Experimental study on density, thermal conductivity, specific heat, and viscosity of water-ethylene glycol mixture dispersed with carbon nanotubes

2017 ◽  
Vol 21 (1 Part A) ◽  
pp. 255-265 ◽  
Author(s):  
Jayabalan Ganeshkumar ◽  
Durai Kathirkaman ◽  
Kandhaswamy Raja ◽  
Vellisamy Kumaresan ◽  
Ramalingam Velraj
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Specific Heat ◽  
Fold Increase ◽  
Modified Model ◽  
Multi Wall Carbon Nanotubes ◽  
Conductivity Enhancement ◽  
Mwcnt Concentration ◽  
Nanoparticle Aggregates

This article presents the effect of adding multi wall carbon nanotubes (MWCNT) in water ? ethylene glycol mixture on density and various thermophysical properties such as thermal conductivity, specific heat and viscosity. Density of nanofluids was measured using standard volumetric flask method and the data showed a good agreement with the mixing theory. The maximum thermal conductivity enhancement of 11 % was noticed for the nanofluids with 0.9 wt. %. Due to lower specific heat of the MWCNT, the specific heat of the nanofluids decreased in proportion with the MWCNT concentration. The rheological analysis showed that the transition region from shear thinning to Newtonian extended to the higher shear stress range compared to that of base fluids. Viscosity ratio of the nanofluids augmented anomalously with respect to increase in temperature and about 2.25 fold increase was observed in the temperature range of 30 ? 40 ?C. The modified model of Maron and Pierce predicted the viscosity of the nanofluids with the inclusion of effect of aspect ratio of MWCNT and nanoparticle aggregates.

scholarly journals Thermal Conductivity and Photothermal Conversion Performance of Ethylene Glycol-Based Nanofluids Containing Multiwalled Carbon Nanotubes

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Nguyen Trong Tam ◽  
Pham Van Trinh ◽  
Nguyen Ngoc Anh ◽  
Nguyen Tuan Hong ◽  
Phan Ngoc Hong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Tween 80 ◽  
Solar Simulator ◽  
Multiwalled Carbon ◽  
Solar Absorption ◽  
Photothermal Conversion ◽  
Conductivity Enhancement ◽  
Conversion Performance

In this study, the successful hydroxyl functionalization of carbon nanotubes (MWCNT-OH) was prepared by chemical treatments and characterized by Raman and FTIR spectra. MWCNT-OH was successfully dispersed into ethylene glycol (EG) with the Tween-80 surfactant by an ultrasonication method to prepare nanofluids. Thermal conductivity of nanofluid was investigated, and a maximum thermal conductivity enhancement about 24% at 50°C was obtained with nanofluid containing 0.64 vol.% MWCNT concentration. The photothermal conversion performance of nanofluid was also investigated by measuring the change of the temperature under lighting from a solar simulator. The measurement results showed that the highest photothermal conversion was obtained about 4.2% after a 30 min lighting with nanofluid containing 0.48 vol.% CNT concentration compared to ethylene glycol. These obtained results have propose a potential application of CNTs in nanofluids for solar absorption.

A model for thermal conductivity of carbon nanotubes with ethylene glycol/water based nanofluids

2017 ◽  
Vol 59 (02) ◽  
pp. 10-13
Author(s):  
Trong Tam Nguyen ◽  
◽  
Hung Thang Bui ◽  
Ngoc Minh Phan ◽  
◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Water Based

Role of Transversal Phonon Modes in the Specific Heat Capacity of Multi-Wall Carbon Nanotubes

2009 ◽  
Vol 6 (5) ◽  
pp. 1200-1203 ◽  
Author(s):  
Mahmoud Jafari ◽  
Seyyed Farhad Masoudi ◽  
Majid Vaezzadeh ◽  
Leila Bohloli Oskoui
Keyword(s):  
Carbon Nanotubes ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Phonon Modes ◽  
Multi Wall Carbon Nanotubes

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.

Thermal Conductivity Measurement for Carbon-Nanotube Suspensions with 3ω Method

2009 ◽  
Vol 60-61 ◽  
pp. 394-398 ◽  
Author(s):  
Gen Sheng Wu ◽  
Jue Kuan Yang ◽  
Shu Lin Ge ◽  
Yu Juan Wang ◽  
Min Hua Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Volume Fraction ◽  
Aqueous Suspension ◽  
Conductivity Measurement ◽  
3Ω Method ◽  
Conductivity Enhancement ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes

The stable and homogeneneous aqueous suspension of carbon nanotubes was prepared in this study. The stability of the nanofluids was improved greatly due to the use of a new dispersant, humic acid. The thermal conductivity of the aqueous suspension was measured with the 3ω method. The experimental results showed that the thermal conductivity of the suspensions increases with the temperature and also is nearly proportional to the loading of the nanoparticles. The thermal conductivity enhancement of single-walled carbon nanotubes (SWNTs) suspensions is better than that of the multi-walled carbon nanotubes (MWNTs) suspensions. Especially for a volume fraction of 0.3846% SWNTs, the thermal conductivity is enhanced by 40.5%. Furthermore, the results at 30°C match well with Jang and Choi’s model.

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.

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