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.

Material Behavior of Porous Media

2013 ◽  
Vol 816-817 ◽  
pp. 42-46
Author(s):  
Leila Remache ◽  
Nacerddine Djermane
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Moisture Content ◽  
Physical Properties ◽  
Control Volume ◽  
Material Behavior ◽  
Control Volume Method ◽  
Mercury Intrusion ◽  
Continuous Approach ◽  
Volume Method

The drying of porous media is studied in this paper by means of the continuous approach and the control volume method. Both transport phenomena inside the porous medium and overall drying kinetics are analyzed. The model utilized in this study requires a lot of physical properties. All of them have been established experimentally. The capillary pressure, which depends on the moisture content, is obtained by a mercury intrusion curve.

Characterization of Transport Properties in Porous Media of a PEM Fuel Cell

2012 ◽  
Author(s):  
Lalit M. Pant ◽  
Sushanta K. Mitra ◽  
Marc Secanell
Keyword(s):  
Porous Media ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Mass Transport ◽  
Transport Properties ◽  
Experimental Studies ◽  
Effective Diffusivity ◽  
Theoretical Models ◽  
Gas Diffusion ◽  
Fuel Cell Performance

Porous media is an essential part of polymer electrolyte membrane fuel cells (PEMFC). In order to optimize fuel cell performance and reduce catalyst consumption, mass transport in fuel cells needs to be improved. Understanding and modelling of mass transport in porous media of fuel cell (e.g. gas diffusion layer (GDL), micro porous layer (MPL) etc.) requires a knowledge of transport properties like diffusivity, permeability and Knudsen diffusivity. Current research is focused on experimental measurement of transport properties of porous media. A counter-diffusion bridge (Wicke-Kallenbach setup) has been used to estimate permeability, Knudsen diffusivity and effective diffusivity of GDLs and MPLs. The obtained transport properties are used with the recent theoretical models of multicomponent mass transport to estimate transport in fuel cells. The experimental studies show that conventional effective approximations like Bruggeman correlations are highly overpredicting and do not fully account for all the frictional forces in porous media.

scholarly journals PORE SIZE DISTRIBUTION IN SIMULATION OF MASS TRANSPORT IN POROUS MEDIA: A CASE STUDY IN RESERVOIR ANALYSIS

2018 ◽  
Vol 56 (2A) ◽  
pp. 24-30
Author(s):  
Vu Hong Thai
Keyword(s):  
Porous Media ◽  
Mass Transport ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Transport Properties ◽  
Size Distribution ◽  
Control Volume ◽  
Mass Conservation ◽  
Absolute Permeability ◽  
Transport In Porous Media

The modeling and numerical simulation of mass transport in porous media is discussed in this work by using the so-called pore size distribution for computing transport properties. The pore-size distribution is a property of the pore structure of a porous medium. This can be used to estimate the different transport properties, amongst other, the permeability. By starting with a formula for the absolute permeability, the simulation of water and oil transport in reservoirs is considered by solving mass conservation equations with the help of the control volume method. The influence of the pore size distribution on the transport behavior is discussed to demonstrate the adequacy of the use of pore size distribution in studying the behavior of reservoirs.

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.

PERMEABILITY AND DIFFUSION COEFFICIENT PREDICTION OF FRACTAL POROUS MEDIA WITH NANOSCALE PORES FOR GAS TRANSPORT

2018 ◽  
Vol 21 (12) ◽  
pp. 1253-1263
Author(s):  
Ruifei Wang ◽  
Hongqing Song ◽  
Jiulong Wang ◽  
Yuhe Wang
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Gas Transport ◽  
And Diffusion

COLUMBIUM 15W-5Mo-1Zr

Alloy Digest ◽  
1969 ◽  
Vol 18 (12) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Structural Properties ◽  
Base Alloy ◽  
Heat Treating ◽  
Temperature Performance

Abstract Columbium 15W-5 Mo- 1Zr is a columbium-base alloy capable of retaining usuable structural properties up to 2500 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Cb-17. Producer or source: Fansteel Metallurgical Corporation.

scholarly journals Experimental study of the supercritical CO 2 diffusion coefficient in porous media under reservoir conditions

2019 ◽  
Vol 6 (6) ◽  
pp. 181902 ◽  
Author(s):  
Junchen Lv ◽  
Yuan Chi ◽  
Changzhong Zhao ◽  
Yi Zhang ◽  
Hailin Mu
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Oil Recovery ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Elevated Pressure ◽  
Experimental Results ◽  
Saturated Porous Media ◽  
Reservoir Conditions ◽  
The Impact

Reliable measurement of the CO 2 diffusion coefficient in consolidated oil-saturated porous media is critical for the design and performance of CO 2 -enhanced oil recovery (EOR) and carbon capture and storage (CCS) projects. A thorough experimental investigation of the supercritical CO 2 diffusion in n -decane-saturated Berea cores with permeabilities of 50 and 100 mD was conducted in this study at elevated pressure (10–25 MPa) and temperature (333.15–373.15 K), which simulated actual reservoir conditions. The supercritical CO 2 diffusion coefficients in the Berea cores were calculated by a model appropriate for diffusion in porous media based on Fick's Law. The results show that the supercritical CO 2 diffusion coefficient increases as the pressure, temperature and permeability increase. The supercritical CO 2 diffusion coefficient first increases slowly at 10 MPa and then grows significantly with increasing pressure. The impact of the pressure decreases at elevated temperature. The effect of permeability remains steady despite the temperature change during the experiments. The effect of gas state and porous media on the supercritical CO 2 diffusion coefficient was further discussed by comparing the results of this study with previous study. Based on the experimental results, an empirical correlation for supercritical CO 2 diffusion coefficient in n -decane-saturated porous media was developed. The experimental results contribute to the study of supercritical CO 2 diffusion in compact porous media.

Mass Transport Modelling in Porous Media Using Delay Differential Equations

2006 ◽  
Vol 258-260 ◽  
pp. 586-591
Author(s):  
António Martins ◽  
Paulo Laranjeira ◽  
Madalena Dias ◽  
José Lopes
Keyword(s):  
Porous Media ◽  
Differential Equations ◽  
Mass Transport ◽  
Delay Differential Equations ◽  
Dispersion Model ◽  
Flow Characteristics ◽  
Convective Transport ◽  
Transport Modelling ◽  
Flow Field Characteristics ◽  
Delay Differential

In this work the application of delay differential equations to the modelling of mass transport in porous media, where the convective transport of mass, is presented and discussed. The differences and advantages when compared with the Dispersion Model are highlighted. Using simplified models of the local structure of a porous media, in particular a network model made up by combining two different types of network elements, channels and chambers, the mass transport under transient conditions is described and related to the local geometrical characteristics. The delay differential equations system that describe the flow, arise from the combination of the mass balance equations for both the network elements, and after taking into account their flow characteristics. The solution is obtained using a time marching method, and the results show that the model is capable of describing the qualitative behaviour observed experimentally, allowing the analysis of the influence of the local geometrical and flow field characteristics on the mass transport.

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