Journal ArticleDOI
Anomalous thermal conductivity enhancement in nanotube suspensions
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TLDR
In this paper, the authors have produced nanotube-in-oil suspensions and measured their effective thermal conductivity, which is anomalously greater than theoretical predictions and is nonlinear with nanotubes loadings.Abstract:
We have produced nanotube-in-oil suspensions and measured their effective thermal conductivity. The measured thermal conductivity is anomalously greater than theoretical predictions and is nonlinear with nanotube loadings. The anomalous phenomena show the fundamental limits of conventional heat conduction models for solid/liquid suspensions. We have suggested physical concepts for understanding the anomalous thermal behavior of nanotube suspensions. In comparison with other nanostructured materials dispersed in fluids, the nanotubes provide the highest thermal conductivity enhancement, opening the door to a wide range of nanotube applications.read more
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Assessment of Relevant Physical Phenomena Controlling Thermal Performance of Nanofluids
TL;DR: In this paper, the authors provide an overview of the important physical phenomena necessary for the determination of effective thermal conductivity of nanofluids, and develop upper and lower bounds for steady-state conduction in stationary ndluids.
Journal ArticleDOI
Convective Performance of Nanofluids in a Laminar Thermally Developing Tube Flow
Abstract: While many of the published papers on nanofluids focus on measuring the increased thermal conductivity of the suspension under static conditions, the convective performance of these fluids has received relatively little attention. The present work measures the effective thermal conductivity of nanofluids under developing convective boundary layer conditions in tubes of diameter 5 mm. The experiments use a hydrodynamically fully developed laminar tube flow in the range 500Re1600 with constant wall heat flux. The experiments were validated through measurements on pure de-ionized (DI) water, which results in a thermal conductivity value that agrees within 0.4% of handbook value. The increase in effective thermal conductivity for DI-water/Al2O3 nanofluids is 6% for 2% volume concentration of Al2O3, which is consistent with the previously reported conductivity values for this sample. For a suspension of multiwall carbon nanotubes in silicone oil, the thermal conductivity is increased by 10% over that of the base fluid for a concentration of 0.2% by volume. Scanning electron microscopy was utilized to examine the structure of the dry state of the nanotubes and elucidate the performance differences of carbon nanomaterials. DOI: 10.1115/1.3013831
Journal ArticleDOI
Cooling performance of a microchannel heat sink with nanofluids containing cylindrical nanoparticles (carbon nanotubes)
TL;DR: In this paper, a numerical method for explaining the cooling performance of a microchannel heat sink with carbon nanotubes (CNTs)-fluid suspensions is presented, where the authors show that with increase of nanolayer thickness of multiwalled carbon-nanotubes, the micro channel heat sink temperature gradient will decrease.
Journal ArticleDOI
Heat transfer of nanofluids in turbulent pipe flow
TL;DR: In this article, the authors studied the heat transfer of nanoparticle suspensions in turbulent pipe flow and derived an optimal particle loading for either maximum heat transfer at constant driving power or minimum cost of operation at constant heat transfer rate.
Journal ArticleDOI
Analysis of hydromagnetic natural convection radiative flow of a viscoelastic nanofluid over a stretching sheet with Soret and Dufour effects
TL;DR: In this paper, a steady, two-dimensional natural convection flow of a viscoelastic, incompressible, electrically conducting and optically thick heat-radiating nanofluid over a linearly stretching sheet in the presence of uniform transverse magnetic field taking Dufour and Soret effects into account is assessed.
References
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Journal ArticleDOI
Helical microtubules of graphitic carbon
TL;DR: Iijima et al. as mentioned in this paper reported the preparation of a new type of finite carbon structure consisting of needle-like tubes, which were produced using an arc-discharge evaporation method similar to that used for fullerene synthesis.
Book
A Treatise on Electricity and Magnetism
TL;DR: The most influential nineteenth-century scientist for twentieth-century physics, James Clerk Maxwell (1831-1879) demonstrated that electricity, magnetism and light are all manifestations of the same phenomenon: the electromagnetic field as discussed by the authors.
Book
Physical properties of carbon nanotubes
TL;DR: In this paper, an introductory textbook for graduate students and researchers from various fields of science who wish to learn about carbon nanotubes is presented, focusing on the basic principles behind the physical properties and giving the background necessary to understand the recent developments.
Journal ArticleDOI
Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles
TL;DR: In this paper, it was shown that a "nanofluid" consisting of copper nanometer-sized particles dispersed in ethylene glycol has a much higher effective thermal conductivity than either pure or pure glycol or even polyethylene glycol containing the same volume fraction of dispersed oxide nanoparticles.
Journal ArticleDOI
Thermal Conductivity of Heterogeneous Two-Component Systems
R. L. Hamilton,O. K. Crosser +1 more
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