GAS DIFFUSION COEFFICIENT OF FRACTAL POROUS MEDIA BY MONTE CARLO SIMULATIONS

Fractals ◽  
2015 ◽  
Vol 23 (02) ◽  
pp. 1550012 ◽  
Author(s):  
QIAN ZHENG ◽  
XIANGPENG LI
Keyword(s):  
Porous Media ◽  
Monte Carlo ◽  
Diffusion Coefficient ◽  
Monte Carlo Simulations ◽  
Pore Size ◽  
Structural Parameters ◽  
Probability Model ◽  
Fractal Dimensions ◽  
Gas Diffusion ◽  
Monte Carlo Simulation Technique

Gas diffusion behavior in fractal porous media is simulated by Monte Carlo technique in this work. Based on the fractal character of pore size in porous media, the probability model of the effective gas diffusion coefficient is derived. The proposed model of the effective gas diffusion coefficient is explicitly expressed as a function of structural parameters of porous media, such as porosity, pore size, the fractal dimensions for pore area and tortuosity. The effect of structural parameters of porous media has been studied in detail. The results show that the present results from the Monte Carlo simulations present a good agreement with those from the available analytical model and the available experimental data. The proposed Monte Carlo simulation technique may have the potential in predictions of other gas transport properties in fractal porous media.

KOZENY–CARMAN CONSTANT FOR GAS FLOW THROUGH FIBROUS POROUS MEDIA BY FRACTAL-MONTE CARLO SIMULATIONS

Fractals ◽  
2019 ◽  
Vol 27 (04) ◽  
pp. 1950062 ◽  
Author(s):  
BOQI XIAO ◽  
XIAN ZHANG ◽  
GUOPING JIANG ◽  
GONGBO LONG ◽  
WEI WANG ◽  
...  
Keyword(s):  
Porous Media ◽  
Monte Carlo ◽  
Fractal Dimension ◽  
Monte Carlo Simulations ◽  
Pore Size ◽  
Fiber Diameter ◽  
Structural Parameters ◽  
Probability Model ◽  
Monte Carlo Technique ◽  
Fibrous Porous Media

In this paper, the Kozeny–Carman constant of fibrous porous media is simulated by the Fractal-Monte Carlo technique. The proposed probability model of the Kozeny–Carman constant is obtained based on the fractal distribution of pore size in fibrous porous media, and thus can be expressed as a function of structural parameters of fibrous porous media, including porosity, micro-pore size, fiber diameter, tortuosity fractal dimension and area fractal dimension of pores. Our results demonstrate that the Kozeny–Carman constant of fibrous porous media increases with increases in tortuosity fractal dimension and fiber diameter. Our results also illustrate a satisfying agreement of the Fractal Monte-Carlo simulations obtained by the proposed model and the existing experimental data. Therefore, the proposed Fractal-Monte Carlo technique can be used to characterize other transport properties of fluid in fibrous porous media.

EFFECTIVE THERMAL CONDUCTIVITY OF POROUS MEDIA WITH ROUGHENED SURFACES BY FRACTAL-MONTE CARLO SIMULATIONS

Fractals ◽  
2020 ◽  
Vol 28 (02) ◽  
pp. 2050029 ◽  
Author(s):  
BOQI XIAO ◽  
SHUAI WANG ◽  
YAN WANG ◽  
GUOPING JIANG ◽  
YIDAN ZHANG ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Porous Media ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Effective Thermal Conductivity ◽  
Structural Parameters ◽  
Monte Carlo Model ◽  
Maximum Diameter ◽  
Empirical Constant ◽  
Relative Roughness

In this paper, the Fractal-Monte Carlo has been employed to simulate the effective thermal conductivity of porous media with roughened surfaces. The proposed probability model for the effective thermal conductivity of porous media with roughened surfaces can be expressed as a function of the relative roughness, porosity, minimum and maximum diameter of pores, fractal dimensions, and random number. The proposed model is validated by a satisfying agreement of our Fractal-Monte Carlo simulations and the experimental data. In our Fractal-Monte Carlo model, there is no extra empirical constant and each parameter has clear physical meaning. Then, the effects of micro-structural parameters of porous media on the effective thermal conductivity of porous media with roughened surfaces have been analyzed in detail. It can be found that the effective thermal conductivity of porous media with roughened surfaces decreases with the increase of relative roughness and tortuosity fractal dimension. Our results demonstrate that the proposed Fractal-Monte Carlo model can be used to characterize other transport properties such as mass transfer of porous media.

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.

Moisture Effective Diffusivity in Porous Media with Different Physical Properties

2006 ◽  
Vol 258-260 ◽  
pp. 207-212
Author(s):  
Miranda M.N.N. ◽  
M.A. Silva
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Moisture Content ◽  
Mass Transport ◽  
Physical Properties ◽  
Pore Size ◽  
Structural Properties ◽  
Effective Diffusivity ◽  
Nay Zeolite ◽  
Moisture Effective Diffusivity

In the drying of porous media, the mass transport occurs in the pores as well as on the surface of the solid. The mechanisms involved can take place simultaneously, influenced by the predominant one and can change depending on the moisture content. In this work, the moisture effective diffusivity was estimated in solids with distinct structural properties in order to verify the predominant mechanisms according to the moisture content, analyzing the influence of the physical properties. The materials studied were NaY Zeolite, Kaolin, Silica and Alumina. The results of diffusion coefficient present a minimum at low moisture content that can be related to pore size.

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