Experimental Study on Thermophysical Properties of Nanotubes and Nanofluids

2007 ◽  
Author(s):  
Xing Zhang ◽  
Motoo Fujii
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Experimental Study ◽  
Thermophysical Properties ◽  
Experimental Studies ◽  
Spherical Nanoparticles ◽  
Hot Wire ◽  
Transient Short Hot Wire ◽  
Different Diameters ◽  
Thermal Conductivities

This paper reviews the studies of the thermophysical properties of nanotubes and nanofluids and reports the experimental studies on the thermal conductivity of individual carbon nanotubes and nanofluids containing spherical and cylindrical nanoparticles. The thermal conductivity of a single carbon nanotube has been measured by a suspended sample-attached T-type nanosensor. The size effect of the different diameters on the thermal conductivity has been observed experimentally. The effective thermal conductivity and thermal diffusivity of Au/toluene, Al2O3/water, TiO2/water, CuO/water and carbon nanofibers (CNFs)/water nanofluids have been measured by using the transient short-hot-wire technique. The measured results demonstrate that the effective thermal conductivities of CNFs/water nanofluids are much greater than those of nanofluids containing spherical nanoparticles. However, the effective thermal conductivities do not show any anomalous enhancements and can be accurately predicted by the existing formulas.

Thermal Conductivity Measurement of Hydrogen at High Pressure and High Temperature

2011 ◽  
Author(s):  
Koichi Kimura ◽  
Shogo Moroe ◽  
Peter Woodfield ◽  
Jun Fukai ◽  
Kan’ei Shinzato ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Pressure Range ◽  
Conductivity Measurement ◽  
Good Reproducibility ◽  
Hot Wire ◽  
Wire Method ◽  
Transient Short Hot Wire ◽  
Thermal Diffusivities ◽  
Thermal Conductivities

The thermal conductivities and thermal diffusivities of hydrogen were measured with a transient short hot wire method for temperature range up to 300 °C and pressure range up to 100MPa. The measured thermal conductivities showed good reproducibility and agreed with the existing values within a deviation of ±2%.

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.

Experimental Study on the Thermal Physical Properties of a CNTS-Ammonia Binary Nanofluid

2008 ◽  
Author(s):  
Xuehu Ma ◽  
Fengmin Su ◽  
Zhong Lan ◽  
Jiabin Chen
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Experimental Study ◽  
Surface Tension ◽  
Physical Properties ◽  
Mass Fraction ◽  
Experimental Values ◽  
Thermal Physical Properties ◽  
Thermal Conductivities

In this paper, carbon nanotubes—ammonia nanofluids (the binary nanofluids) have been prepared by two steps method. And the thermal conductivity, surface tension and kinetic viscosity of the binary nanofluid have been measured. The effects of the mass fraction of carbon nanotubes, the concentration of ammonia and temperature on the thermal physical properties of the binary nanofluid have been systematically studied. On the base, the effective thermal conductivities of the binary nanofluids have been calculated using the models in the literatures, and have been compared with the experimental values.

Design of a Steady-State, Parallel-Plate Thermal Conductivity Apparatus for Nanofluids and Comparative Measurements With Transient HWTC Apparatus

2010 ◽  
Author(s):  
Milivoje M. Kostic ◽  
Casey J. Walleck
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Parallel Plate ◽  
Measurement Method ◽  
Mixture Theory ◽  
Hot Wire ◽  
Electro Magnetic ◽  
Magnetic Phenomena ◽  
Thermal Conductivities

A steady-state, parallel-plate thermal conductivity (PPTC) apparatus has been developed and used for comparative measurements of complex POLY-nanofluids, in order to compare results with the corresponding measurements using the transient, hotwire thermal conductivity (HWTC) apparatus. The related measurements in the literature, mostly with HWTC method, have been inconsistent and with measured thermal conductivities far beyond prediction using the well-known mixture theory. The objective was to check out if existing and well-established HWTC method might have some unknown issues while measuring TC of complex nano-mixture suspensions, like electro-magnetic phenomena, undetectable hot-wire vibrations, and others. These initial and limited measurements have shown considerable difference between the two methods, where the TC enhancements measured with PPTC apparatus were about three times smaller than with HWTC apparatus, the former data being much closer to the mixture theory prediction. However, the influence of measurement method is not conclusive since it has been observed that the complex nano-mixture suspensions were very unstable during the lengthy steady-state measurements as compared to rather quick transient HWTC method. The nanofluid suspension instability might be the main reason for very inconsistent results in the literature. It is necessary to expend investigation with more stable nano-mixture suspensions.

THE THERMAL CONDUCTIVITY OF DEUTERIUM

1935 ◽  
Vol 12 (3) ◽  
pp. 372-376 ◽  
Author(s):  
A. B. Van Cleave ◽  
O. Maass
Keyword(s):  
Thermal Conductivity ◽  
Hydrogen Molecule ◽  
Hydrogen Isotopes ◽  
Hot Wire ◽  
Wire Method ◽  
Deuterium Molecule ◽  
Thermal Conductivities

The thermal conductivities of deuterium and some mixtures of deuterium and hydrogen have been measured by a relative, "hot wire" method. The results are consistent with the authors' original conclusion that the deuterium molecule has the same molecular diameter as the hydrogen molecule. It follows also that the molecular heats of the hydrogen isotopes are the same.

scholarly journals Application and testing of a new simple experimental set-up for thermal conductivity measurements of liquids

2017 ◽  
Vol 21 (3) ◽  
pp. 1195-1202 ◽  
Author(s):  
Andrej Stanimirovic ◽  
Emila Zivkovic ◽  
Nenad Milosevic ◽  
Mirjana Kijevcanin
Keyword(s):  
Thermal Conductivity ◽  
Measurement Uncertainty ◽  
Thermophysical Properties ◽  
Deionized Water ◽  
Conductivity Measurements ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
New Apparatus ◽  
Wire Method ◽  
Set Up

Transient hot wire method is considered a reliable and precise technique for measuring the thermal conductivity of liquids. The present paper describes a new transient hot wire experimental set-up and its initial testing. The new apparatus was tested by performing thermal conductivity measurements on substances whose reference thermophysical properties data existed in literature, namely on pure toluene and double distilled deionized water. The values of thermal conductivity measured in the temperature range 25 to 45 ?C deviated +2.2% to +3% from the literature data, while the expanded measurement uncertainty was estimated to be ?4%.

scholarly journals Numerical Simulation of Natural Convection in a Transient Short-Hot-Wire Thermal Conductivity Cell

Netsu Bussei ◽  
2008 ◽  
Vol 22 (4) ◽  
pp. 217-222 ◽  
Author(s):  
Peter L. Woodfield ◽  
Jun Fukai ◽  
Motoo Fujii ◽  
Yasuyuki Takata ◽  
Kanei Shinzato
Keyword(s):  
Thermal Conductivity ◽  
Numerical Simulation ◽  
Natural Convection ◽  
Hot Wire ◽  
Transient Short Hot Wire ◽  
Thermal Conductivity Cell ◽  
Conductivity Cell

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 properties of pillared-graphene nanostructures

2015 ◽  
Vol 1727 ◽  
Author(s):  
M. Rifu ◽  
K. Shintani
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Molecular Dynamics ◽  
Thermal Properties ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Nonequilibrium Molecular Dynamics ◽  
Nonequilibrium Molecular Dynamics Simulation ◽  
Thermal Conductivities ◽  
Graphene Nanostructures

ABSTRACTThe thermal conductivities of pillared-graphene nanostructures (PGNSs) are obtained using nonequilibrium molecular-dynamics simulation. It is revealed their thermal conductivities are much smaller than the thermal conductivities of carbon nanotubes (CNTs). This fact is explained by examining the density of states (DOS) of the local phonons of PGNSs. It is also found the thermal conductivity of a PGNS linearly decreases with the increase of the inter-pillar distance.

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