Water Based Multiwalled Carbon Nanotube Nanofluids With Optimized Thermal Conductivity

2009 ◽  
Author(s):  
Li Fei Chen ◽  
Huaqing Xie ◽  
Wei Yu ◽  
Yang Li
Keyword(s):  
Thermal Conductivity ◽  
Ball Milling ◽  
Volume Fraction ◽  
Free Water ◽  
Strong Acid ◽  
Multiwalled Carbon ◽  
Conductivity Enhancement ◽  
Water Based ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

We report a method to prepare surfactant-free water based nanofluids containing multi-walled carbon nanotubes (CNTs). The as prepared CNTs with hard dispersibility, after being cut by mechanical ball-milling approach following strong acid treatment, can be directly dispersed into water. The thermal conductivity of the nanofluids is optimized by controlling the CNT length and straightness. It is realized by changed the ball-milling times. The thermal conductivity enhancement of water based CNT nanofluids with volume fraction of 1% attains 29.5% by controlling the CNT length and straightness when the temperature is 63.9°C.

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.

Enhanced Thermal Conductivity of Nanofluid by Synergistic Effect of Multi-Walled Carbon Nanotubes and Fe2O3 Nanoparticles

2014 ◽  
Vol 548-549 ◽  
pp. 118-123 ◽  
Author(s):  
Li Fei Chen ◽  
Min Cheng ◽  
De Jun Yang ◽  
Lei Yang
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Synergistic Effect ◽  
Interfacial Adhesion ◽  
Conductivity Enhancement ◽  
Hybrid Fillers ◽  
Water Based ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Enhanced Thermal Conductivity

This study investigates the synergistic effect of combining multi-walled carbon nanotubes (MWNTs) and Fe2O3nanoparticles on thermal conductivity of nanofluid. Results show that low percentage hybrid fillers loading improve thermal conductivity of water based nanofluid, due to the good dispersion and interfacial adhesion, which is confirmed by scanning electron microscope. Furthermore, the hybrid fillers provide synergistic effect on heat conductive networks. The thermal conductivity enhancement of water based nanofluid containing 0.05 wt % MWNTs and 0.02 wt % Fe2O3nanoparticles is 27.75%, which is higher than that of nanofluid containing 0.2 wt % single MWNTs or Fe2O3nanoparticles.

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 Thermophysical Properties of IoNanofluids Composed of 1-ethyl-3-methylimidazolium Thiocyanate and Carboxyl-functionalized Long Multi-walled Carbon Nanotubes

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 214
Author(s):  
Bertrand Jóźwiak ◽  
Justyna Dziadosz ◽  
Adrian Golba ◽  
Krzysztof Cwynar ◽  
Grzegorz Dzido ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Carboxylic Group ◽  
Conductivity Enhancement ◽  
Multi Walled Carbon Nanotubes ◽  
Vibrating Tube Densimeter ◽  
Carbon Based Nanomaterials ◽  
Walled Carbon Nanotubes ◽  
Rotary Viscometer

The concept of IoNanofluids (INFs) as the stable dispersions of nanoparticles in ionic liquids was proposed in 2009 by Nieto de Castro’s group. INFs characterize exciting properties such as improved thermal conductivity, non-volatility, and non-flammability. This work is a continuation of our studies on the morphology and physicochemistry of carbon-based nanomaterials affecting thermal conductivity, viscosity, and density of INFs. We focus on the characterization of dispersions composed of long carboxylic group-functionalized multi-walled carbon nanotubes and 1-ethyl-3-methylimidazolium thiocyanate. The thermal conductivity of INFs was measured using KD2 Pro Thermal Properties Analyzer (Decagon Devices Inc., Pullman, WA, USA). The viscosity was investigated using rotary viscometer LV DV-II+Pro (Brookfield Engineering, Middleboro, MA, USA). The density of INFs was measured using a vibrating tube densimeter Anton Paar DMA 5000 (Graz, Austria). The maximum thermal conductivity enhancement of 22% was observed for INF composed of 1 wt% long carboxylic group-functionalized multi-walled carbon nanotubes.

Study on the Thermal Characteristics of Heat Pipes with Water-Based MWCNT Nanofluids

2011 ◽  
Vol 110-116 ◽  
pp. 1879-1885
Author(s):  
Hyo Jun Ha ◽  
Ji Hun Park ◽  
Seok Pil Jang
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Thermal Resistance ◽  
Heat Pipe ◽  
Volume Fraction ◽  
Thermal Characteristics ◽  
Heat Pipes ◽  
Multiwalled Carbon ◽  
Evaporation Temperature ◽  
Water Based

In this paper, thermal characteristics of miniature heat pipes with grooved wick and water-based multiwalled carbon nanotubes(MWCNT) nanofluids(0.1, 0.2, and 0.5 vol.%) as working fluids are experimentally investigated. The thermal conductivity and thermal resistances are measured and compared with those of DI water. The thermal conductivity of water-based MWCNT nandfluids is enhanced by up to 29% compared with that of DI water. Experiments are performed under the same evaporation temperature condition. The thermal resistance of heat pipe is reduced from 30% to 35.2% as the volume fraction of nanoparticles inceasing from 0.1% to 0.5%. Finally, based on the experimental results, we present the reduction of the thermal resistances of the heat pipes compared with conventional heat pipes cannot be explained by only the thermal conductivity of water-based MWCNT nanofluids.

scholarly journals Preparation and Rheological Properties of Amide-based Multiwalled Carbon Nanotube Mirabilite Phase Change Materials

2021 ◽  
Vol 3 (2) ◽  
pp. 86-91
Author(s):  
Yu Zhang ◽  
Shengnian Tie
Keyword(s):  
Composite Material ◽  
Carbon Nanotube ◽  
Phase Change ◽  
Phase Change Materials ◽  
Volume Fraction ◽  
Temperature Fluctuations ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The multi-walled carbon nanotubes (MWCNTs) are modified by redox methods, and the surface groups of the MWCNTs are analyzed by infrared spectroscopy. And the modified MWCNTs were added to the mirabilite-based phase change materials (PCMs) at 40°C to prepare the mirabilite-based phase change composite material. The results show that when the volume fraction is 0.05% and 0.25%, when the temperature rises from 30°C to 50°C, the viscosity drop of the phase change composite material is 35.86% and 37.50%, respectively. That is, the larger the volume of the fraction of nanoparticles, the higher the viscosity, thus the greater the ability to perceive temperature fluctuations. In addition, the amide multiwalled carbon nanotube mirabilite PCMs was placed for 30 days, and the dispersion stability was good, and no phase delamination occurred.

Preparation of Stable Silicon Oil Based Nanofluid Containing Multi-Walled Carbon Nanotube by Using Hexamethyldisiloxane as Dispersant

2010 ◽  
Author(s):  
Lifei Chen ◽  
Huaqing Xie ◽  
Yang Li ◽  
Wei Yu
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Silicone Oil ◽  
Strong Acid ◽  
Transfer Enhancement ◽  
Scanning Electronic Microscopy ◽  
Multi Walled Carbon Nanotube ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
The Ideal

Stable and homogeneous silicone oil based nanofluids of multi-walled carbon nanotubes (MWNTs) were prepared by using hexamethyldisiloxane as surfactant. The used MWNTs were cut by mechanical ball-milling approach following strong acid treatment. Scanning electronic microscopy results show that the MWNTs disperse well in the silicone oil. The addition of hexamethyldisiloxane reduces the viscosity of silicone oil greatly in all the studied temperatures. It is different from some water based nanofluids with surfactant. The minor viscosity augmentation of silicone oil based MWNT nanofluid with high thermal conductivity make it the ideal media in high burden of heat transfer and heat transfer enhancement in special condition. As expected, the viscosity of the nanofluid increases with MWNT volume fraction, but decreases with temperature. The 0.54 vol% MWNT dispersions with the addition of 0.6 wt % hexamethyldisiloxane show no MWNT precipitation for a couple of weeks.

Morphology Origin of Gradually Weakened Thermal-Conductivity Enhancement for HDPE/MWCNTs Nanocomposites

2016 ◽  
Author(s):  
Xiao-Hong Yin ◽  
Can Yang ◽  
Shiju E ◽  
Xiping Li ◽  
Jianbo Cao
Keyword(s):  
Thermal Conductivity ◽  
Phonon Scattering ◽  
Loss Modulus ◽  
Low Frequency ◽  
Complex Viscosity ◽  
Thermal Conductivity Enhancement ◽  
Mwcnt Content ◽  
Conductivity Enhancement ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this work, high-density polyethylene/multi-walled carbon nanotubes (HDPE/MWCNTs) nanocomposites containing various filler loadings (i.e., 0.5∼16.0 wt.%) were prepared with their thermal conductivities determined using a laser-based analyzer. It was found that although the nanocomposite’s thermal conductivity increased with elevated MWCNT content, the enhancement degree lowered gradually. Rheology and microstructure characterizations were performed to reveal the morphology origin of gradually weakened thermal-conductivity enhancement. The dynamic rheology measurements showed that all nanocomposites exhibited higher storage modulus (G′), loss modulus (G″) as well as complex viscosity (η*) compared with the neat HDPE. More interestingly, the plateau of the flow regime formed at low frequency ranges with MWCNT loadings higher than 2.0 wt.% suggested the formation of the MWNCT network structures within the nanocomposites. The existence of such structures was further verified by the Cole-Cole curves obtained from the rheology testing and MWCNT distribution states from scanning electron microscope (SEM) results. The formation of MWCNT network lowered the degree of thermal-conductivity enhancement in such a way that it gave a larger possibility for MWCNTs to agglomerate, which led to phonon scattering that reduced the nanocomposite’s thermal conductivity.

scholarly journals Tuning the length dispersion of multi-walled carbon nanotubes by ball milling

AIP Advances ◽  
2013 ◽  
Vol 3 (9) ◽  
pp. 092117 ◽  
Author(s):  
László Forró ◽  
Richard Gaal ◽  
Claudio Grimaldi ◽  
Marijana Mionić ◽  
Primož Rebernik Ribič ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Ball Milling ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes
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