Measuring Thermal Conductivity of Fluids Containing Oxide Nanoparticles

1999 ◽  
Vol 121 (2) ◽  
pp. 280-289 ◽  
Author(s):  
S. Lee ◽  
S. U.-S. Choi ◽  
S. Li ◽  
J. A. Eastman
Keyword(s):  
Thermal Conductivity ◽  
Particle Shape ◽  
Experimental Results ◽  
Oxide Nanoparticles ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Transient Hot Wire Method ◽  
Wire Method ◽  
Al2o3 Particles ◽  
Thermal Conductivities

Oxide nanofluids were produced and their thermal conductivities were measured by a transient hot-wire method. The experimental results show that these nanofluids, containing a small amount of nanoparticles, have substantially higher thermal conductivities than the same liquids without nanoparticles. Comparisons between experiments and the Hamilton and Crosser model show that the model can predict the thermal conductivity of nanofluids containing large agglomerated Al2O3 particles. However, the model appears to be inadequate for nanofluids containing CuO particles. This suggests that not only particle shape but size is considered to be dominant in enhancing the thermal conductivity of nanofluids.

Effect of Volume Fraction and Temperature on Thermal Conductivity of SiO2 Nanofluids

2011 ◽  
Vol 306-307 ◽  
pp. 1178-1181 ◽  
Author(s):  
Bao Jie Zhu ◽  
Wei Lin Zhao ◽  
Dong Dong Li ◽  
Jin Kai Li
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Volume Fraction ◽  
Experimental Results ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Transient Hot Wire Method ◽  
Wire Method ◽  
Thermal Conductivities

Thermal conductivities of two kinds of nanofluids (SiO2-water and SiO2-ethylene glycol) were measured by transient hot-wire method at different volume fraction and temperature. Influences of volume fraction of particles and temperature on thermal conductivities of nanofluids were analyzed. The Experimental results show that thermal conductivities of nanofluids are higher than those of base fluids, and increase with the increase of volume fraction and temperature. When approximately 0.5% volume fraction of SiO2nanoparticles are added into water and ethylene glycol at the temperature 50°C, the thermal conductivities are enhanced 46.2% and 62.8% respectively.

Ultra-High Temperature Thermal Conductivity Measurements of a Reactive Magnesium Manganese Oxide Porous Bed Using a Transient Hot Wire Method

2021 ◽  
Author(s):  
Michael Hayes ◽  
Faezeh Masooomi ◽  
Philipp Schimmels ◽  
Kelvin Randhir ◽  
James Klausner ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Manganese Oxide ◽  
Effective Thermal Conductivity ◽  
Phonon Transport ◽  
Experimental Results ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Transient Hot Wire Method ◽  
Proposed Model ◽  
Wire Method

Abstract The effective thermal conductivity of packed beds of magnesium-manganese oxide pellets is a crucial parameter for engineering Magnesium Manganese Oxide (Mg-Mn-O) thermochemical energy storage devices. We have measured the effective thermal conductivity of a packed bed of 3.66 ±0.516 mm sized magnesium manganese oxide (Mn to Mg molar ratio of 1:1) pellets in the temperature range of 300 to 1400°C. Since the material is electrically conductive at temperatures above 600°C, the sheathed transient hot wire method is used for measurements. Raw data is analyzed using the Blackwell solution to extract the bed thermal conductivity. The effective thermal conductivity standard deviation is less than 10% for a minimum of three repeat measurements at each temperature. Experimental results show an increase in the effective thermal conductivity with temperature from 0.50 W/m °C around 300°C to 1.81 W/m °C close to 1400°C. We propose a dual porosity model to express the effective thermal conductivity as a function of temperature. This model also considers the effect of radiation within the bed, as this is the dominant heat transfer mode at high temperatures. The proposed model accounts for micro-scale pellet porosity, macro-scale bed porosity, pellet size, solid thermal conductivity (phonon transport), and radiation (photon transport). The coefficient of determination between the proposed model and the experimental results is greater than 0.90.

Analysis of the Transient Hot-Wire Method to Measure Thermal Conductivity of Silica Aerogel: Influence of Wire Length, and Radiation Properties

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Ellann Cohen ◽  
Leon Glicksman
Keyword(s):  
Thermal Conductivity ◽  
Silica Aerogel ◽  
Test Method ◽  
Wire Radius ◽  
Wire Length ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
End Effects ◽  
Transient Hot Wire Method ◽  
Wire Method

When the transient hot-wire method is used to measure the thermal conductivity of very low thermal conductivity silica aerogel (in the range of 10 mW/m·K at 1 atm) end effects due to the finite wire size and radiation corrections must be considered. An approximate method is presented to account for end effects with realistic boundary conditions. The method was applied to small experimental samples of the aerogel using different wire lengths. Initial conductivity results varied with wire length. This variation was eliminated by the use of the end effect correction. The test method was validated with the NIST (National Institute of Standards and Technology) Standard Reference Material 1459, fumed silica board to within 1 mW/m·K. The aerogel is semitransparent. Due to the small wire radius and short transient, radiation heat transfer may not be fully accounted for. In a full size aerogel panel radiation will augment the phonon conduction by a larger amount.

scholarly journals A Study on Thermal Conductivity of Mixture of Magnesia Particle and Molten Nitrate by a Transient Hot Wire Method

Netsu Bussei ◽  
2005 ◽  
Vol 19 (3) ◽  
pp. 142-146 ◽  
Author(s):  
Kazuyuki Kitano ◽  
Katsuya Hanyuda ◽  
Eisyun Takegoshi ◽  
Masatoshi Sawada ◽  
Yoshio Hirasawa ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Transient Hot Wire Method ◽  
Wire Method
Sign in / Sign up

Export Citation Format

Share Document