Temperature and Pressure Dependences of the Effective Thermal Conductivity of Granites

AbstractNovel carbon foam with high thermal conductivity is prepared by thermal treating of mesophase pitch under certain temperature and pressure condition. With fractal theory, the thermal conducting property of this novel porous material is discussed. Then we deduce the area fractal dimension of carbon foam. A thermal conductivity model of carbon foam is proposed. The relationship formula of effective thermal conductivity is presented by using thermal resistance method. Through computation, the effective thermal conductivity of carbon foam is acquired. The value of model forecast is consistent with that of the actual observed for carbon foam. This method has provided the theoretical basis for better using its fine heat conduction performance.

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Temperature and Pressure Dependence of the Effective Thermal Conductivity of Geomaterials: Numerical Investigation by the Immersed Interface Method

Journal of Applied Mathematics ◽

10.1155/2013/456931 ◽

2013 ◽

Vol 2013 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Duc Phi Do ◽

Dashnor Hoxha

Keyword(s):

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Numerical Procedure ◽

Numerical Approach ◽

Diffusion Problem ◽

Immersed Interface Method ◽

Immersed Interface ◽

Imperfect Interfaces ◽

Linear Behavior ◽

Temperature And Pressure

The present work aims to study the nonlinear effective thermal conductivity of heterogeneous composite-like geomaterials by using a numerical approach based on the immersed interface method (IIM). This method is particularly efficient at solving the diffusion problem in domains containing inner boundaries in the form of perfect or imperfect interfaces between constituents. In this paper, this numerical procedure is extended in the framework of non linear behavior of constituents and interfaces. The performance of the developed tool is then demonstrated through the studies of temperature- and pressure-dependent effective thermal conductivity of geomaterials with imperfect interfaces.

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On the temperature and pressure dependences of the effective thermal conductivity of granites

Thermal Science ◽

10.2298/tsci200408176e ◽

2020 ◽

pp. 176-176

Author(s):

Subkhanverdi Emirov ◽

Abutrab Aliverdiev ◽

Vetlugin Beybalaev ◽

Anise Amirova

Keyword(s):

Thermal Conductivity ◽

Temperature Dependence ◽

Effective Thermal Conductivity ◽

Power Law ◽

Atmospheric Pressure ◽

Experimental Measurements ◽

Pressure Behavior ◽

Stationary Method ◽

Temperature And Pressure ◽

Granite Samples

The results of experimental measurements of the temperature dependence of the effective thermal conductivity of various granite samples obtained by the absolute stationary method in the temperature and pressure ranges of 273- 523 K and 0.1-400 MPa, respectively, are analyzed. The power-law character of the temperature dependence of the effective thermal conductivity for all measured granite samples at atmospheric pressure is established. We have shown that pressure significantly affects the power law of the temperature dependence of the effective thermal conductivity of granite samples. A low-parameter description of the temperature-pressure behavior of thermal conductivity is proposed. A correlation is established between its components.

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Compact Analytical Models of Effective Thermal Conductivity of Rough Spheroid Packed Beds

Heat Transfer, Volume 2 ◽

10.1115/imece2004-60129 ◽

2004 ◽

Cited By ~ 4

Author(s):

M. Bahrami ◽

M. M. Yovanovich ◽

J. R. Culham

Keyword(s):

Experimental Data ◽

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Present Model ◽

Thermal Analyses ◽

Contact Load ◽

Analytical Models ◽

Packed Beds ◽

Wide Range ◽

Temperature And Pressure

New compact analytical models for predicting the effective thermal conductivity of regularly packed beds of rough spheres immersed in a stagnant gas are developed. Existing models do not consider either the influence of the spheres roughness or the rarefaction of the interstitial gas on the conductivity of the beds. Contact mechanics and thermal analyses are performed for uniform size spheres packed in SC and FCC arrangements and the results are presented in the form of compact relationships. The present model accounts for the thermophysical properties of spheres and the gas, contact load, spheres diameter, spheres roughness and asperities slope, and temperature and pressure of the gas. The present model is compared with experimental data for SC and FCC packed beds and good agreement is observed. The experimental data cover a wide range of the contact load, surface roughness, interstitial gas type, and gas temperature and pressure.

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An Experimental Study of Effective Thermal Conductivity of High Temperature Insulations

Journal of Heat Transfer ◽

10.1115/1.2804946 ◽

2008 ◽

Vol 130 (3) ◽

Cited By ~ 6

Author(s):

Bo-ming Zhang ◽

Wei-hua Xie ◽

Shan-yi Du ◽

Shu-yuan Zhao

Keyword(s):

Thermal Conductivity ◽

Effective Thermal Conductivity ◽

Maximum Temperature ◽

Environmental Pressures ◽

Average Temperature ◽

Experimental Apparatus ◽

History Of ◽

Temperature And Pressure ◽

Transfer Mechanisms ◽

Thermal Conductivities

An experimental apparatus was designed and fabricated to measure the effective thermal conductivities and simulate the temperature and pressure history of reentry of a launch vehicle into a planetary atmosphere with a maximum temperature of 1600°C. An improved testing method was used to test the thermal conductivities of an alumina fibrous insulation at environmental pressures from 0.03Pato105Pa with the average temperature of the sample increased to 864°C and its density being 128kg∕m3. A method based on temperature difference is used to compute the in-plane effective thermal conductivity, and the result shows that the in-plane thermal conductivity along the y axis is 1.47 times that along the x axis. The influences of temperature and pressure on the contribution of three heat transfer mechanisms to the effective thermal conductivities were compared.

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