Experimental and theoretical studies of effective thermal conductivity of composites made of silicone rubber and Al2O3 particles

2015 ◽  
Vol 614 ◽  
pp. 1-8 ◽  
Author(s):  
B.Z. Gao ◽  
J.Z. Xu ◽  
J.J. Peng ◽  
F.Y. Kang ◽  
H.D. Du ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Silicone Rubber ◽  
Theoretical Studies ◽  
Al2o3 Particles ◽  
Experimental And Theoretical Studies

Measurement of Effective Thermal Conductivity of CNT-Nanofluids by Transient Short-Wire Method

2009 ◽  
Author(s):  
Masamichi Kohno ◽  
Koichi Kimura ◽  
Shogo Moroe ◽  
Yasuyuki Takata ◽  
Peter L. Woodfield ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Effective Thermal Conductivity ◽  
Volume Fraction ◽  
Hot Wire ◽  
Wire Method ◽  
Different Shapes ◽  
Transient Short Hot Wire ◽  
Al2o3 Particles ◽  
Particle Shapes

Thermal conductivity and thermal diffusivity of CNT-nanofluids and Al2O3-nanofulids were measured by the transient short-hot-wire method. The uncertainty of their measurements is estimated to be within 1% for the thermal conductivity and 5% for the thermal diffusivity. Three different shapes of Al2O3 particles were prepared for Al2O3–water nanofluids. For the thermal conductivity of Al2O3-water nanofluids, there are differences in the enhancement of thermal conductivity for differences in particle shapes. Hardly any enhancement of thermal conductivity was observed for SWCNT-water nanofluids because the volume fraction of SWCNT was extremely low. However, we consider by increasing the volume fraction of SWCNTs, it will be possible to enhance the thermal conductivity.

An Apparatus for Measuring the Effective Thermal Conductivity of the Body Surface

1999 ◽  
Author(s):  
Shuxia Cheng ◽  
Hongbo Zhang ◽  
Dawei Luo ◽  
Dayong Gao
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Body Surface ◽  
Silicone Rubber ◽  
The Body ◽  
Platinum Wire ◽  
Time Interval ◽  
The Wire ◽  
Predetermined Time

Abstract To prevent body from injury during the hyper- and hypo-thermic therapy, knowledge of the temperature distribution in the body surface (e.g. skin or tissue) close to the therapy location is needed. In order to predict, by calculation, the correct temperature field, it is essential to input meaningful values of the thermal properties of the body surface into numerical and analytical simulation models of its behavior during heating or cooling. A simple experimental apparatus for measuring effective thermal conductivity of the body surface has been developed. It differs from the previously developed apparatus. In experiments, a fine platinum wire (0.01 mm in diameter) with electrical resistance R (0.4Ω)is embedded between a tested specimen (body surface) and a silicone rubber. When the wire, specimen and rubber are in thermal equilibrium, and a constant electrical power is applied to the wire, the temperature increase of the wire against logarithm time in predetermined time interval was measured. The kinetics of this temperature rising is related to the thermal conductivity of the tested specimen and silicone rubber. The thermal conductivity of the silicone rubber is known from reference or measured. So the thermal conductivity of tested specimen can be calculated by measuring the temperature rise of platinum wire at predetermined time interval. It is assumed that (1) the wire is infinite long and the heat source is steady, (2) the tested medium (e.g. the tested specimen and the silicone rubber) are infinite large in space, and contact resistance between the fine wire and soft medium is negligible. The apparatus’ validity has been demonstrated by the following tests. First, as the standard specimen, thermal conductivity of glycerol and fused quartz glass (99.9% SiO2) were respectively measured using the apparatus. The relative errors between measured thermal conductivity and data provided by Thermophysical Properties Research Center (TPRC) are less than 0.7%. The validity of the theory model was also confirmed using several inorganic specimens and biological materials (e.g. rabbit sin, in vivo). Conditions and prerequisites for application of the technique and apparatus to measuring thermal conductivity of biomaterials (in vivo) were discussed.

scholarly journals Thermal and Hydraulic Performance of CuO/Water Nanofluids: A Review

Micromachines ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 416 ◽  
Author(s):  
Mohammad Yacoub Al Shdaifat ◽  
Rozli Zulkifli ◽  
Kamaruzzaman Sopian ◽  
Abeer Adel Salih
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Volume Fraction ◽  
Hydraulic Performance ◽  
Theoretical Studies ◽  
Pumping Power ◽  
Large Particle Size ◽  
Experimental And Theoretical Studies ◽  
The Heat Transfer Coefficient

This paper discusses the behaviour of different thermophysical properties of CuO water-based nanofluids, including the thermal and hydraulic performance and pumping power. Different experimental and theoretical studies that investigated each property of CuO/water in terms of thermal and fluid mechanics are reviewed. Classical theories cannot describe the thermal conductivity and viscosity. The concentration, material, and size of nanoparticles have important roles in the heat transfer coefficient of CuO/water nanofluids. Thermal conductivity increases with large particle size, whereas viscosity increases with small particle size. The Nusselt number depends on the flow rate and volume fraction of nanoparticles. The causes for these behaviour are discussed. The magnitude of heat transfer rate is influenced by the use of CuO/water nanofluids. The use of CuO/water nanofluids has many issues and challenges that need to be classified through additional studies.

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