Determination of effective thermal conductivity for real porous media using fractal theory

1999 ◽  
Vol 8 (2) ◽  
pp. 102-107 ◽  
Author(s):  
Yongping Chen ◽  
Mingheng Shi
Keyword(s):  
Thermal Conductivity ◽  
Porous Media ◽  
Effective Thermal Conductivity ◽  
Fractal Theory

scholarly journals Thermal Dispersion in Porous Media—A Review on the Experimental Studies for Packed Beds

2013 ◽  
Vol 65 (3) ◽  
Author(s):  
Türküler Özgümüş ◽  
Moghtada Mobedi ◽  
Ünver Özkol ◽  
Akira Nakayama
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Porous Media ◽  
Effective Thermal Conductivity ◽  
Experimental Studies ◽  
Experimental Methods ◽  
Packed Beds ◽  
Thermal Dispersion ◽  
Heat Addition

Thermal dispersion is an important topic in the convective heat transfer in porous media. In order to determine the heat transfer in a packed bed, the effective thermal conductivity including both stagnant and dispersion thermal conductivities should be known. Several theoretical and experimental studies have been performed on the determination of the effective thermal conductivity. The aim of this study is to review the experimental studies done on the determination of the effective thermal conductivity of the packed beds. In this study, firstly brief information on the definition of the thermal dispersion is presented and then the reported experimental studies on the determination of the effective thermal conductivity are summarized and compared. The reported experimental methods are classified into three groups: (1) heat addition/removal at the lateral boundaries, (2) heat addition at the inlet/outlet boundary, (3) heat addition inside the bed. For each performed study, the experimental details, methods, obtained results, and suggested correlations for the determination of the effective thermal conductivity are presented. The similarities and differences between experimental methods and reported studies are shown by tables. Comparison of the correlations for the effective thermal conductivity is made by using figures and the results of the studies are discussed.

Determination of the effective thermal conductivity of the porous media based on digital rock physics

Geothermics ◽  
2021 ◽  
Vol 97 ◽  
pp. 102267
Author(s):  
Du Dongxing ◽  
Zhang Xu ◽  
Wan Chunhao ◽  
Liu Jiaqi ◽  
Shen Yinjie ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Porous Media ◽  
Effective Thermal Conductivity ◽  
Rock Physics ◽  
Digital Rock Physics ◽  
Digital Rock

PREDICTION OF EFFECTIVE THERMAL CONDUCTIVITY OF POROUS MEDIA WITH FRACTAL-MONTE CARLO SIMULATIONS

Fractals ◽  
2014 ◽  
Vol 22 (03) ◽  
pp. 1440004 ◽  
Author(s):  
YOUSHENG XU ◽  
YOUQU ZHENG ◽  
JIANLONG KOU
Keyword(s):  
Thermal Conductivity ◽  
Porous Media ◽  
Monte Carlo ◽  
Fractal Dimension ◽  
Effective Thermal Conductivity ◽  
Scaling Laws ◽  
Volume Fraction ◽  
Probability Model ◽  
Fractal Theory ◽  
Monte Carlo Simulation Technique

On the basis of the fractal scaling laws of pore distribution in natural porous media, a probability model is developed for thermal conductivity in porous media by combining fractal theory and Monte Carlo technique. The current numerical model, which was validated by comparison with the existing experimental data, shows that the thermal conductivity of porous media is a function of the thermal conductivities of volume fraction, pore area fractal dimension, tortuosity fractal dimension and random number. The effect of microstructure parameters on the effective thermal conductivity of porous media is studied. The proposed fractal Monte Carlo simulation technique has advantages compared with conventional numerical methods and may have the potential in analyzing other transport properties of porous media.

scholarly journals Effective Thermal Conductivity of Open Cell Polyurethane Foam Based on the Fractal Theory

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Kan Ankang ◽  
Han Houde
Keyword(s):  
Thermal Conductivity ◽  
Fractal Dimension ◽  
Effective Thermal Conductivity ◽  
Polyurethane Foam ◽  
Solid Phase ◽  
Fractal Theory ◽  
Heat Radiation ◽  
Total Thermal Conductivity ◽  
Equivalent Thermal Conductivity ◽  
Open Cell

Based on the fractal theory, the geometric structure inside an open cell polyurethane foam, which is widely used as adiabatic material, is illustrated. A simplified cell fractal model is created. In the model, the method of calculating the equivalent thermal conductivity of the porous foam is described and the fractal dimension is calculated. The mathematical formulas for the fractal equivalent thermal conductivity combined with gas and solid phase, for heat radiation equivalent thermal conductivity and for the total thermal conductivity, are deduced. However, the total effective heat flux is the summation of the heat conduction by the solid phase and the gas in pores, the radiation, and the convection between gas and solid phase. Fractal mathematical equation of effective thermal conductivity is derived with fractal dimension and vacancy porosity in the cell body. The calculated results have good agreement with the experimental data, and the difference is less than 5%. The main influencing factors are summarized. The research work is useful for the enhancement of adiabatic performance of foam materials and development of new materials.

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