scholarly journals Thermal Conductivity of CNT - Wated Nanofluids: a Review

2020 ◽  
Vol 22 (1) ◽  
pp. 207-220 ◽  
Author(s):  
M. Akhilesh ◽  
K. Santarao ◽  
M. V. S. Babu
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Experimental Studies ◽  
Thermal Characteristics ◽  
Thermal Conducting ◽  
The Stability ◽  
Proper Group ◽  
Physical Stabilization ◽  
Transportation Applications

AbstractIn heat transportation applications, water is most commonly used fluid. The efficiency of equipment used in these applications depends on thermal characteristics of water used. The thermal characteristics of water could be upgraded by suspending high thermal conducting solid nanoparticles. In this paper an attempt has been made to know how the use of surfactants and functionalization of carbon nanotube walls can affect the thermal characteristics and stability of nanofluid. A thorough analysis of collected literature revealed that carbon nanotubes have much higher thermal conductivity than any other nanoparticles and hence improve the thermal properties of water when suspended in them. Further it is concluded that suspension of carbon nanotubes in water requires use of surfactant or functionalization of carbon nanotube walls with proper group. By setting optimum pH and better dispersion, better thermal conductivity is possible. Experimental studies in the literature survey reveal that chemical stabilization techniques and physical stabilization techniques together decide the stability of the nanofluid.

A closed-form model for estimating the effective thermal conductivities of carbon nanotube–polymer nanocomposites

2018 ◽  
Vol 233 (8) ◽  
pp. 2909-2919 ◽  
Author(s):  
Reza Moheimani ◽  
M Hasansade
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Closed Form ◽  
Polymer Nanocomposites ◽  
Micromechanical Model ◽  
Polymer Nanocomposite ◽  
Interfacial Thermal Resistance ◽  
Full Potential ◽  
Thermal Conductivities

This paper describes a closed-form unit cell micromechanical model for estimating the effective thermal conductivities of unidirectional carbon nanotube reinforced polymer nanocomposites. The model incorporates the typically observed misalignment and curvature of carbon nanotubes into the polymer nanocomposites. Also, the interfacial thermal resistance between the carbon nanotube and the polymer matrix is considered in the nanocomposite simulation. The micromechanics model is seen to produce reasonable agreement with available experimental data for the effective thermal conductivities of polymer nanocomposites reinforced with different carbon nanotube volume fractions. The results indicate that the thermal conductivities are strongly dependent on the waviness wherein, even a slight change in the carbon nanotube curvature can induce a prominent change in the polymer nanocomposite thermal conducting behavior. In general, the carbon nanotube curvature improves the nanocomposite thermal conductivity in the transverse direction. However, using the straight carbon nanotubes leads to maximum levels of axial thermal conductivities. With the increase in carbon nanotube diameter, an enhancement in nanocomposite transverse thermal conductivity is observed. Also, the results of micromechanical simulation show that it is necessary to form a perfectly bonded interface if the full potential of carbon nanotube reinforcement is to be realized.

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.

Experimental Study on the Thermal Boundary Resistance Between an Individual Carbon Nanotube End and a Au Surface

2011 ◽  
Author(s):  
Jun Hirotani ◽  
Tatsuya Ikuta ◽  
Takashi Nishiyama ◽  
Koji Takahashi
Keyword(s):  
Thermal Conductivity ◽  
Experimental Study ◽  
Carbon Nanotube ◽  
Experimental Studies ◽  
Boundary Resistance ◽  
Thermal Boundary Resistance ◽  
The Past ◽  
Experiment Method ◽  
Very High ◽  
Intrinsic Thermal Conductivity

In the past decade, the very high intrinsic thermal conductivity of a carbon nanotube (CNT) has been successfully unveiled through experimental studies, but the thermal boundary resistance (TBR) between a CNT and ambient material still remains unclear. Some analytical and molecular dynamics studies have been reported on the TBR between a CNT and a surrounding material but there is no reliable experiment method to quantitatively investigate TBR between a CNT and a solid surface because of technical difficulties.

scholarly journals Thermophysical Properties of Nanofluids Composed of Ethylene Glycol and Long Multi-Walled Carbon Nanotubes

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 241
Author(s):  
Karolina Brzóska ◽  
Bertrand Jóźwiak ◽  
Adrian Golba ◽  
Marzena Dzida ◽  
Sławomir Boncel
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Chemical Vapor ◽  
Step Method ◽  
Mwcnt Content ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes ◽  
Rotary Viscometer

In this work, thermal conductivity, viscosity, isobaric heat capacity, and density of stable carbon-based nanofluids are presented. The nanofluids under study are composed of 1,2-ethanediol (ethylene glycol, EG) and long multi-walled carbon nanotubes (MWCNTs), so-called ‘in-house 16h’ (synthesized in our laboratory via catalytic chemical vapor deposition during 16 h with a diameter of 60–80 nm and length of 770 μm). Poly(N-vinylpyrrolidone) (PVP) was used to increase the stability of nanofluids. The nanofluids were prepared via an ultrasonication-assisted, three-step method while their key thermophysical characteristics were obtained using the hot-wire technique and rotary viscometer. As a result, the addition of MWCNTs significantly improved the thermal conductivity of nanofluids by 31.5% for the highest 1.0 wt% (0.498 vol%) long MWCNT content, leaving the Newtonian character of the nanofluids practically intact.

A Flow Sensor for Liquids Based on Single-Walled Carbon Nanotube Thin Films

2007 ◽  
Vol 121-123 ◽  
pp. 75-79 ◽  
Author(s):  
C.L. Cao ◽  
Liang Fang ◽  
K.J. Liao ◽  
F.J. Wei ◽  
L. Li
Keyword(s):  
Thin Films ◽  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Angular Velocity ◽  
Experimental Studies ◽  
Chemical Vapor ◽  
Flow Sensor ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Electron Drag

An angular velocity of flow sensor for liquids based on single-walled carbon nanotube thin films is presented. The carbon nanotubes in this study were fabricated on Si substrate by hot filament chemical vapor deposition (CVD). The experimental results showed that the flow-induced current on the surface of carbon nanotube thin films was closely depended upon the angular velocity, concentration, properties and temperature of the liquids. The current increased with increasing angular velocity, concentration and temperature of the liquids. In this study, the liquids such as water, NaCl solution and other electrolyte were flowing over the sensor. The results obtained were also discussed. The theoretical and experimental studies have shown that there was electronic friction and electron drag effect of carbon nanotubes in flowing liquids. This effect in carbon nanotubes can be used for a new flow sensor.

Carbon nanotube-copper exhibiting metal-like thermal conductivity and silicon-like thermal expansion for efficient cooling of electronics

Nanoscale ◽  
2014 ◽  
Vol 6 (5) ◽  
pp. 2669-2674 ◽  
Author(s):  
Chandramouli Subramaniam ◽  
Yuzuri Yasuda ◽  
Satoshi Takeya ◽  
Seisuke Ata ◽  
Ayumi Nishizawa ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Carbon Nanotube ◽  
Cooling Of Electronics

A composite that synergistically combines the best thermal properties of carbon nanotubes and copper is developed for efficient cooling of microelectronics.

Measurements of the Intrinsic Thermal Conductivity of Individual Multi-Wall Carbon Nanotubes

2011 ◽  
Author(s):  
Juekuan Yang ◽  
Scott W. Waltermire ◽  
Yang Yang ◽  
Deyu Li ◽  
Yunfei Chen
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Heat Source ◽  
Thermal Resistance ◽  
Effective Thermal Conductivity ◽  
Experimental Studies ◽  
Contact Thermal Resistance ◽  
Multi Wall Carbon Nanotubes ◽  
The Past ◽  
Thermal Conductivities

Thermal transport through carbon nanotubes (CNTs) attracted a lot of attention over the past decade. Several experimental studies have been carried out to determine the thermal conductivities of CNTs [1–3]. However, the measurements are based on an individual CNT sample between two suspended membranes and the results actually include both the intrinsic thermal resistance of the CNT and the contact thermal resistance between the CNT and the two suspended membranes that serve as a heat source and a heat sink. Hence, the effective thermal conductivity extracted from these measurements should be lower than the intrinsic thermal conductivities of the CNTs measured. To minimize the contact thermal resistance, electron beam induce deposition (EBID) of different metals has been used to increase the contact area between the CNT and the heat source and sink [3,4]. However, it is still not clear how effective this treatment is and to what level the effective thermal conductivity obtained after the EBID treatment reflects the intrinsic one.

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