Identification of the Thermal Conductivity Coefficient in the Three-Dimensional Case by Solving a Corresponding Optimization Problem

2021 ◽  
Vol 61 (9) ◽  
pp. 1416-1431
Author(s):  
A. F. Albu ◽  
V. I. Zubov
Keyword(s):  
Thermal Conductivity ◽  
Optimization Problem ◽  
Thermal Conductivity Coefficient ◽  
Three Dimensional ◽  
Dimensional Case

Analysis of the Sintered Porous Brick Wall Insulation Performance Using Different Ways Masonry

2015 ◽  
Vol 1092-1093 ◽  
pp. 550-554
Author(s):  
Jian Long Liu ◽  
Jie Nan Xie ◽  
Peng Liu ◽  
Mu Ye Huang
Keyword(s):  
Thermal Conductivity ◽  
Void Ratio ◽  
Thermal Conductivity Coefficient ◽  
Three Dimensional ◽  
Masonry Wall ◽  
Brick Wall ◽  
Equivalent Thermal Conductivity ◽  
Insulation Effect ◽  
Heat Transfers ◽  
Insulation Performance

Through the three-dimensional heat transfers numerical simulation of eight kinds with the different number of holes, void ratio and arrangement of sintered shale porous brick (size: 240mm×190mm×90mm), which simulate the sintered porous brick under two different laying way that is 240mm wall and 190mm wall of equivalent thermal conductivity. The result shows: the same kind of porous brick as 240mm wall and 190mm wall, when the equivalent thermal conductivity coefficient has phased difference that the wall insulation effect is obviously different. Through the analysis of two different methods of the masonry wall thermal insulation performance of the influence by different reasons, targeted to put forward some suggestions in order to improve calorific performance of the wall.

Structure and Thermoelectric Properties of New Quaternary Tin and Lead Bismuth Selenides, K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1+xSn5-xBi11+xSe22

2000 ◽  
Vol 626 ◽  
Author(s):  
Antje Mrotzek ◽  
Kyoung-Shin Choi ◽  
Duck-Young Chung ◽  
Melissa A. Lane ◽  
John R. Ireland ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Single Crystal ◽  
Thermoelectric Properties ◽  
Three Dimensional ◽  
Structure Type ◽  
Narrow Gap ◽  
Low Thermal Conductivity ◽  
Seebeck Coefficients ◽  
Metal Atoms ◽  
Anionic Framework

ABSTRACTWe present the structure and thermoelectric properties of the new quaternary selenides K1+xM4–2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22. The compounds K1+xM4-2xBi7+xSe15 (M= Sn, Pb) crystallize isostructural to A1+xPb4-2xSb7+xSe15 with A = K, Rb, while K1-xSn5-xBi11+xSe22 reveals a new structure type. In both structure types fragments of the Bi2Te3-type and the NaCl-type are connected to a three-dimensional anionic framework with K+ ions filled tunnels. The two structures vary by the size of the NaCl-type rods and are closely related to β-K2Bi8Se13 and K2.5Bi8.5Se14. The thermoelectric properties of K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22 were explored on single crystal and ingot samples. These compounds are narrow gap semiconductors and show n-type behavior with moderate Seebeck coefficients. They have very low thermal conductivity due to an extensive disorder of the metal atoms and possible “rattling” K+ ions.

Preparation, microstructure and properties of three-dimensional carbon/carbon composites with high thermal conductivity

Carbon ◽  
2021 ◽  
Vol 174 ◽  
pp. 758-759
Author(s):  
Bao-liu Li ◽  
Jian-guang Guo ◽  
Bing Xu ◽  
Hui-tao Xu ◽  
Zhi-jun Dong ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Three Dimensional ◽  
High Thermal Conductivity ◽  
Carbon Composites ◽  
Microstructure And Properties

The effect of variable properties and rotation in a visco-thermoelastic orthotropic annular cylinder under the Moore–Gibson–Thompson heat conduction model

2021 ◽  
pp. 146442072098589
Author(s):  
Ahmed E Aboueregal ◽  
Hamid M Sedighi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Stresses ◽  
Thermal Conductivity Coefficient ◽  
Variable Properties ◽  
Transformation Technique ◽  
Present Contribution ◽  
Conduction Model ◽  
Thermoelastic Model ◽  
Shock Heating ◽  
Physical Fields

The present contribution aims to address a problem of thermoviscoelasticity for the analysis of the transition temperature and thermal stresses in an infinitely circular annular cylinder. The inner surface is traction-free and subjected to thermal shock heating, while the outer surface is thermally insulated and free of traction. In this work, in contrast to the various problems in which the thermal conductivity coefficient is considered to be fixed, this parameter is assumed to be variable depending on the temperature change. The problem is studied by presenting a new generalized thermoelastic model of thermal conductivity described by the Moore–Gibson–Thompson equation. The new model can be constructed by incorporating the relaxation time thermal model with the Green–Naghdi type III model. The Laplace transformation technique is used to obtain the exact expressions for the radial displacement, temperature and the distributions of thermal stresses. The effects of angular velocity, viscous parameter, and variance in thermal properties are also displayed to explain the comparisons of the physical fields.

scholarly journals Numerical simulation of variable thermal conductivity on 3D flow of nanofluid over a stretching sheet

2020 ◽  
Vol 9 (1) ◽  
pp. 233-243 ◽  
Author(s):  
Nainaru Tarakaramu ◽  
P.V. Satya Narayana ◽  
Bhumarapu Venkateswarlu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Stretching Sheet ◽  
Three Dimensional ◽  
Variable Thermal Conductivity ◽  
Normal Velocity ◽  
Transfer Coefficients ◽  
Similarity Transformations ◽  
Frictional Coefficients ◽  
The Impact

AbstractThe present investigation deals with the steady three-dimensional flow and heat transfer of nanofluids due to stretching sheet in the presence of magnetic field and heat source. Three types of water based nanoparticles namely, copper (Cu), aluminium oxide (Al2O3), and titanium dioxide (TiO2) are considered in this study. The temperature dependent variable thermal conductivity and thermal radiation has been introduced in the energy equation. Using suitable similarity transformations the dimensional non-linear expressions are converted into dimensionless system and are then solved numerically by Runge-Kutta-Fehlberg scheme along with well-known shooting technique. The impact of various flow parameters on axial and transverse velocities, temperature, surface frictional coefficients and rate of heat transfer coefficients are visualized both in qualitative and quantitative manners in the vicinity of stretching sheet. The results reviled that the temperature and velocity of the fluid rise with increasing values of variable thermal conductivity parameter. Also, the temperature and normal velocity of the fluid in case of Cu-water nanoparticles is more than that of Al2O3- water nanofluid. On the other hand, the axial velocity of the fluid in case of Al2O3- water nanofluid is more than that of TiO2nanoparticles. In addition, the current outcomes are matched with the previously published consequences and initiate to be a good contract as a limiting sense.

scholarly journals Advances in Liquid Crystalline Epoxy Resins for High Thermal Conductivity

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1302
Author(s):  
Younggi Hong ◽  
Munju Goh
Keyword(s):  
Thermal Conductivity ◽  
Network Structure ◽  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Random Network ◽  
Three Dimensional ◽  
Heat Insulator ◽  
Liquid Crystalline Epoxy ◽  
Thermally Conductive ◽  
Substantial Interest

Epoxy resin (EP) is one of the most famous thermoset materials. In general, because EP has a three-dimensional random network, it possesses thermal properties similar to those of a typical heat insulator. Recently, there has been substantial interest in controlling the network structure of EP to create new functionalities. Indeed, the modified EP, represented as liquid crystalline epoxy (LCE), is considered promising for producing novel functionalities, which cannot be obtained from conventional EPs, by replacing the random network structure with an oriented one. In this paper, we review the current progress in the field of LCEs and their application to highly thermally conductive composite materials.

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