Effect of initial density on thermal conductivity of new micro‐pipeline heat conduction C/SiC composites

2020 ◽  
Vol 104 (1) ◽  
pp. 645-653
Author(s):  
Yunhai Zhang ◽  
Yongsheng Liu ◽  
Yejie Cao ◽  
Liyang Cao ◽  
Jing Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Initial Density ◽  
Sic Composites

Effect of well-designed graphene heat conductive channel on the thermal conductivity of C/SiC composites

2021 ◽  
Author(s):  
Yunhai Zhang ◽  
Yongsheng Liu ◽  
Yejie Cao ◽  
Liyang Cao ◽  
Xutong Zheng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Conductive Channel ◽  
Sic Composites

scholarly journals Lattice Boltzmann method simulation of the gas heat conduction of nanoporous material

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3749-3756
Author(s):  
Ya Han ◽  
Shuai Li ◽  
Hai-Dong Liu ◽  
Weipeng Cui
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Lattice Boltzmann Method ◽  
Knudsen Number ◽  
Lattice Boltzmann ◽  
Size Effects ◽  
Temperature Jump ◽  
Boundary Scattering ◽  
Nanoporous Material ◽  
Boltzmann Method

In order to deeply investigate the gas heat conduction of nanoporous aerogel, a model of gas heat conduction was established based on microstructure of aerogel. Lattice Boltzmann method was used to simulate the temperature distribution and gas thermal conductivity at different size, and the size effects of gas heat conduction have had been obtained under micro-scale conditions. It can be concluded that the temperature jump on the boundary was not obvious and the thermal conductivity remained basically constant when the value of Knudsen number was less than 0.01; as the value of Knudsen number increased from 0.01 to 0.1, there was a clear temperature jump on the boundary and the thermal conductivity tended to decrease and the effect of boundary scattering increased drastically, as the value of Knudsen number was more than 0.1, the temperature jump increased significantly on the boundary, furtherly, the thermal conductivity decreased dramatically, and the size effects were significantly.

scholarly journals Nonlocal Thermodynamics: Mathematical Model of Two-Dimensional Thermal Conductivity

2021 ◽  
Vol 321 ◽  
pp. 03005
Author(s):  
George Kuvyrkin ◽  
Inga Savelyeva ◽  
Daria Kuvshinnikova
Keyword(s):  
Thermal Conductivity ◽  
Mathematical Model ◽  
Heat Conduction ◽  
Numerical Solution ◽  
Complex Structure ◽  
Modern World ◽  
Nonlocal Term ◽  
Material Structure ◽  
Two Dimensional ◽  
Differential Heat

Nonlocal models of thermodynamics are becoming more and more popular in the modern world. Such models make it possible to describe materials with a complex structure and unique strength and temperature properties. Models of nonlocal thermodynamics of a continuous medium establish a relationship between micro and macro characteristics of materials. A mathematical model of thermal conductivity in nonlocal media is considered. The model is based on the theory of nonlocal continuum by A.K. Eringen. The interaction of material particles is described using local and nonlocal terms in the law of heat conduction. The nonlocal term describes the effect of decreasing the influence of the surrounding elements of the material structure with increasing distance. The effect of nonlocal influence is described using the standard non-locality function based on the Gaussian distribution. The nonlocality function depends on the distance between the elements of the material structure. The mathematical model of heat conduction in a nonlocal medium consists of an integro-differential heat conduction equation with initial and boundary conditions. A numerical solution to the problem of heat conduction in a nonlocal plate is obtained. The numerical solution of a two-dimensional problem based on the finite element method is described. The influence of nonlocal effects and material parameters on the thermal conductivity in a plate under highintensity surface heating is analyzed. The importance of nonlocal characteristics in modelling the thermodynamic behaviour of materials with a complex structure is demonstrated.

scholarly journals Design and Implementation of a Laboratory Equipment for Studying Heat Transfer by Conduction

2019 ◽  
Vol 11 (1) ◽  
pp. 153-156
Author(s):  
István Padrah ◽  
Judit Pásztor ◽  
Rudolf Farmos
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Conduction ◽  
Thermal Conduction ◽  
Transfer Mechanism ◽  
Measuring Instrument ◽  
Heat Transfer Mechanism ◽  
Laboratory Equipment ◽  
Insulating Materials ◽  
Design And Implementation

Abstract Thermal conduction is a heat transfer mechanism. It is present in our everyday lives. Studying thermal conductivity helps us better understand the phenomenon of heat conduction. The goal of this paper is to measure the thermal conductivity of various materials and compare results with the values provided by the manufacturers. To achieve this we assembled a measuring instrument and performed measurements on heat insulating materials.

Heat conduction mechanisms in hot pressed ZrB2 and ZrB2–SiC composites

2013 ◽  
Vol 33 (10) ◽  
pp. 1615-1624 ◽  
Author(s):  
Manish Patel ◽  
V.V. Bhanu Prasad ◽  
Vikram Jayaram
Keyword(s):  
Heat Conduction ◽  
Conduction Mechanisms ◽  
Sic Composites

Numerical Simulation of Thermal Conductivity of Nanofluids

2010 ◽  
Author(s):  
Jing Fan ◽  
Liqiu Wang
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Interfacial Thermal Resistance ◽  
Thermal Conductivity Ratio ◽  
Radius Of Gyration ◽  
Particle Volume ◽  
Geometrical Structures ◽  
Conductivity Enhancement

The recent first-principle model shows a dual-phase-lagging heat conduction in nanofluids at the macroscale. The macroscopic heat-conduction behavior and the thermal conductivity of nanofluids are determined by their molecular physics and microscale physics. We examine numerically effects of particle-fluid thermal conductivity ratio, particle volume fraction, shape, aggregation, and size distribution on macroscale thermal properties for nine types of nanofluids, without considering the interfacial thermal resistance and dynamic processes on particle-fluid interfaces and particle-particle contacting surfaces. The particle radius of gyration and non-dimensional particle-fluid interfacial area in the unit cell are two very important parameters in characterizing the effect of particles’ geometrical structures on thermal conductivity of nanofluids. Nanofluids containing cross-particle networks have conductivity which practically reaches the Hashin-Shtrikman bounds. Moreover, particle aggregation influences the effective thermal conductivity only when the distance between particles is less than the particle dimension. Uniformly-sized particles are desirable for the conductivity enhancement, although to a limited extent.

Anomalous Heat Conduction, Diffusion and Heat Rectification in Nanoscale Structures

2009 ◽  
Author(s):  
Gang Zhang ◽  
Nuo Yang ◽  
Gang Wu ◽  
Baowen Li
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Heat Transport ◽  
Nano Materials ◽  
Fourier Law ◽  
Nanoscale Structures ◽  
Recent Developments ◽  
Theoretical Results ◽  
Good Agreement ◽  
Anomalous Heat

In this paper, we report the recent developments in the study of heat transport in nano materials. First of all, we show that phonon transports in nanotube super-diffusively which leads to a length dependence thermal conductivity, thus breaks down the Fourier law. Then we discuss how the introduction of isotope doping can reduce the thermal conductivity efficiently. The theoretical results are in good agreement with experimental ones. Finally, we will demonstrate that nanoscale structures are promising candidates for heat rectification.

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