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.

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.

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 Enhancement Derived from Poly(Methyl Methacrylate)-Grafted Carbon Nanotubes in Poly(Methyl Methacrylate)/Polystyrene Blends

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1347 ◽  
Author(s):  
Jaehyun Wie ◽  
Jooheon Kim
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Methyl Methacrylate ◽  
Multiwalled Carbon Nanotubes ◽  
Thermal Conductivity Enhancement ◽  
Multiwalled Carbon ◽  
Poly Methyl Methacrylate ◽  
Conductivity Enhancement ◽  
Conductive Properties ◽  
Enhanced Thermal Conductivity

This paper presents a method to enhance thermal conductivity using poly(methyl methacrylate)(PMMA), polystyrene(PS) blends, and incorporation of multiwalled carbon nanotubes (MWCNTs). MWCNTs are selectively localized in PMMA phase to improve conductive properties. In addition, Surface of MWCNTs was treated with PMMA to enhance affinity between matrix and filler. PMMA grafting helps filler localization on matrix phase. Composites using two polymers enhanced thermal conductivity by ~11% compared with composites using only PS or PMMA. Also, PMMA grafting on the surface of MWCNTs enhanced thermal conductivity by ~13% compared with samples without PMMA grafting.

The Influence of Carbon Nanotube Aspect Ratio on Thermal Conductivity Enhancement in Nanotube–Polymer Composites

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Rahul S. Kapadia ◽  
Brian M. Louie ◽  
Prabhakar R. Bandaru
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Aspect Ratio ◽  
Polymer Composites ◽  
Polymer Matrix ◽  
Linear Increase ◽  
Interfacial Resistance ◽  
Multiwalled Carbon ◽  
Conductivity Enhancement

We report and model a linear increase in the thermal conductivity (κ) of polymer composites incorporated with relatively low length/diameter aspect ratio multiwalled carbon nanotubes (CNTs). There was no evidence of percolation-like behavior in the κ, at/close to the theoretically predicted threshold, which was attributed due to the interfacial resistance between the CNT and the polymer matrix. Concomitantly, the widely postulated high thermal conductivity of CNTs does not contribute to the net thermal conductivity of the composites. Through estimating the interfacial resistance and the thermal conductivity of the constituent CNTs, we conclude that our experimental and modeling approaches can be used to study thermal transport behavior in nanotube–polymer composites.

scholarly journals Application of Multiwalled Carbon Nanotube Nanofluid for 450 W LED Floodlight

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Bui Hung Thang ◽  
Le Dinh Quang ◽  
Nguyen Manh Hong ◽  
Phan Hong Khoi ◽  
Phan Ngoc Minh
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
High Power ◽  
Heat Dissipation ◽  
Air Cooling ◽  
Liquid Cooling ◽  
Multiwalled Carbon ◽  
Cooling Method ◽  
High Power Led

Overheating of the high-power light emitting diode (LED) has a dramatic effect on the chip’s lifetime. Heat dissipation for high-power LED is becoming a major challenge for researchers and technicians. Compared with the air cooling method, the liquid cooling method has many advantages and high efficiency because of higher specific heat capacity, density, and thermal conductivity. Carbon nanotubes with remarkable thermal properties have been used as additives in liquids to increase the thermal conductivity. In this work, multiwalled carbon nanotubes nanofluid (MWCNTs nanofluid) was used to enhance heat dissipation for 450 W LED floodlight. MWCNTs nanofluid was made by dispersing the OH functionalized MWCNTs in ethylene glycol/water solution. The concentration of MWCNTs in fluid was in the range between 0.1 and 1.3 gram/liter. The experimental results showed that the saturated temperature of 450 W LED chip was 55°C when using water/ethylene glycol solution in liquid cooling system. In the case of using MWCNTs nanofluid with 1.2 gram/liter of MWCNTs’ concentration, the saturated temperature of LED chip was 50.6°C. The results have confirmed the advantages of the MWCNTs for heat dissipation systems for high-power LED floodlight and other high power electronic devices.

scholarly journals Evaluation of Physicothermal Properties of Solar Thermic Fluids Dispersed with Multiwalled Carbon Nanotubes and Prediction of Data Using Artificial Neural Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
K. Ch. Sekhar ◽  
Raviteja Surakasi ◽  
ilhan Garip ◽  
S. Srujana ◽  
V. V. Prasanna Kumar ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Multiwalled Carbon Nanotubes ◽  
Thermophysical Properties ◽  
Viscosity Measurement ◽  
Multiwalled Carbon ◽  
Constant Thermal Conductivity ◽  
Mathematical Computation ◽  
Surfactant Assisted

A review of multiwalled carbon nanotubes as solar thermic fluids and their thermophysical properties is done in this article. The basic fluids were ethylene glycol and water in ratios of 100 : 0, 90 : 10, and 80 : 20. To investigate how surface modification impacts thermophysical properties, three base fluids were combined with surfactant-assisted MWCNTs and oxidized MWCNTs in weight fractions of 0.125, 0.25, and 0.5 percent, respectively. It takes two months to check whether the dispersion stays constant. Thermal conductivity and viscosity measurement were done using heated discs and Anton Paar viscometers. Using oxidized MWCNTs to disperse, the base fluids increased thermal conductivity by 15% to 24%. Surfactant-assisted MWCNTs in nanofluids perform worse than oxidized MWCNTs. The dynamic viscosity of nanofluids is higher than that of basic fluids between 50 and 70°C. During a mathematical computation, all of the MWCNT weight fractions and ethylene glycol volume percentages are included. The correlation may be a good fit for the experimental data within limits. The characteristics are forecasted using feed-forward backpropagation. In this research, buried layer neurons and factors are examined.

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