The Hydraulic Permeability of Dual Porosity Fibrous Media

2001 ◽  
Vol 20 (10) ◽  
pp. 871-880 ◽  
Author(s):  
B. Markicevic ◽  
T. D. Papathanasiou
Keyword(s):  
Dual Porosity ◽  
Hydraulic Permeability ◽  
Fibrous Media

scholarly journals Development of Permeability Models for Saturated Fluid Flow across Arrays of Fibre Clusters

2002 ◽  
Vol 11 (3) ◽  
pp. 096369350201100
Author(s):  
E.M. Gravel ◽  
T.D. Papathanasiou
Keyword(s):  
Analytical Models ◽  
Dual Porosity ◽  
Hydraulic Permeability ◽  
Fibrous Media ◽  
Fibre Bundles ◽  
Hexagonal Packing ◽  
Composites Manufacturing ◽  
Starting Point ◽  
Wide Range ◽  
Flow Through

Dual porosity fibrous media are important in a number of applications, ranging from bioreactor design and transport in living systems to composites manufacturing. In the present study we are concerned with the development of predictive models for the hydraulic permeability ( Kp) of various arrays of fibre bundles. For this we carry out extensive computations for viscous flow through arrays of fibre bundles using the Boundary Element Method (BEM) implemented on a multi-processor computer. Up to 350 individual filaments, arranged in square or hexagonal packing within bundles, which are also arranged in square of hexagonal packing, are included in each simulation. These are simple but not trivial models for fibrous preforms used in composites manufacturing – dual porosity systems characterised by different inter- and intra-tow porosities. The way these porosities affect the hydraulic permeability of such media is currently unknown and is elucidated through our simulations. Following numerical solution of the governing equations, ( Kp) is calculated from the computed flowrate through Darcy's law and is expressed as function of the inter- and intra-tow porosities (φ, φt) and of the filament radius ( Rf). Numerical results are also compared to analytical models. The latter form the starting point in the development of a dimensionless correlation for the permeability of such dual porosity media. It is found that the numerically computed permeabilities follow that correlation for a wide range of φ i, φt and Rf.

A General Correlation for the Hydraulic Permeability of Arrays of Elliptical Fiber Bundles

2000 ◽  
Author(s):  
E. M. Gravel ◽  
T. D. Papathanasiou
Keyword(s):  
Computational Analysis ◽  
Analytical Models ◽  
Dual Porosity ◽  
Fiber Bundles ◽  
Hydraulic Permeability ◽  
Elliptical Cross ◽  
Single Master Curve ◽  
Flow Through ◽  
The Subject ◽  
Good Agreement

Abstract A computational analysis of viscous flow through arrays of fiber bundles is carried out using the Boundary Element Method. We consider fiber bundles of elliptical cross section, each made up of up to 350 individual filaments. Such arrays are dual-porosity systems, characterized by different inter- (ϕi) and intra-tow (ϕt) porosities as well as by varying number (Nf) of filaments within each bundle. Investigating the influence of these parameters on the hydraulic permeability of hexagonal arrays of such bundles is the subject of our simulations. The results are compared to earlier analytical models and a good agreement is found. A dimensionless correlation is proposed and the computed permeabilities for bundles of aspect ratio λ = 2 and λ = 3 are shown to fall on a single master curve. This offers a generalized model for the calculation of the permeability of such dual porosity systems from knowledge of ϕi, ϕt, λ and Nf.

scholarly journals Hydraulic permeability of (un)bounded fibrous media using the lattice Boltzmann method

2000 ◽  
Vol 61 (1) ◽  
pp. 616-625 ◽  
Author(s):  
D. S. Clague ◽  
B. D. Kandhai ◽  
R. Zhang ◽  
P. M. A. Sloot
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Hydraulic Permeability ◽  
Fibrous Media ◽  
Boltzmann Method

Modeling Interstitial Flow in an Artery Wall Allows Estimation of Wall Shear Stress on Smooth Muscle Cells

1995 ◽  
Vol 117 (3) ◽  
pp. 358-363 ◽  
Author(s):  
D. M. Wang ◽  
J. M. Tarbell
Keyword(s):  
Shear Stress ◽  
Smooth Muscle ◽  
Wall Shear Stress ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Hydraulic Permeability ◽  
Interstitial Flow ◽  
Fibrous Media ◽  
Wall Shear

The arterial media is modeled as a periodic array of cylindrical smooth muscle cells residing in a matrix comprised of proteoglycan and collagen fibers. Using Brinkman’s model to describe transmural flow through such a fibrous media, we calculate the effective hydraulic permeability of the media and the wall shear stress on smooth muscle cells. Two interesting results are obtained: first, the wall shear stress on smooth muscle cells is on the order of 1 dyne/cm2, which is in the range known to affect endothelial cells in vitro; second, the flow resistance due to smooth muscle cells is not negligible compared to the resistance due to the fiber matrix.

Numerical analysis of viscous flow through fibrous media: a model for glomerular basement membrane permeability

1998 ◽  
Vol 274 (1) ◽  
pp. F223-F231 ◽  
Author(s):  
Matteo Palassini ◽  
Andrea Remuzzi
Keyword(s):  
Basement Membrane ◽  
Viscous Flow ◽  
Glomerular Basement Membrane ◽  
Three Dimensional ◽  
Periodic Array ◽  
Hydraulic Permeability ◽  
Fibrous Media ◽  
Ultrastructural Studies ◽  
Dimensionless Ratio ◽  
Flow Through

Viscous flow through fibrous media is characterized macroscopically by the Darcy permeability ( K D). The relationship between K D and the microscopic structure of the medium has been the subject of experimental and theoretical investigations. Calculations of K D based on the solution of the hydrodynamic flow at fiber scale exist in literature only for two-dimensional arrays of parallel fibers. We considered a fiber matrix consisting of a three-dimensional periodic array of cylindrical fibers with uniform radius ( r) and length connected in a tetrahedral structure. According to recent ultrastructural studies, this array of fibers can represent a model for the glomerular basement membrane (GBM). The Stokes flow through the periodic array was simulated using a Galerkin finite element method. The dimensionless ratio K* = K D/ r 2 was determined for values of the fractional solid volume (φ) in the range 0.005 ≤ φ ≤ 0.7. We compared our numerical results, summarized by an interpolating formula relating K* to φ, with previous theoretical determinations of hydraulic permeability in fibrous media. We found a good agreement with the Carman-Kozeny equation only for φ > 0.4. Among the other theoretical analysis considered, only that of Spielman and Goren ( Environ. Sci. Technol. 2: 279–287, 1968) gives satisfactory agreement in the whole range of φ considered. These results can be useful to model combined transport of water and macromolecules through the GBM for the estimation of the radius and length of extracellular protein fibrils.

Characterization of seawater reverse osmosis fouled membranes from large scale commercial desalination plant

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Reverse Osmosis ◽  
Large Scale ◽  
Retention Rate ◽  
Local Level ◽  
Microscopic Analysis ◽  
Transmembrane Pressure ◽  
Hydraulic Permeability ◽  
Seawater Reverse Osmosis ◽  
A Chain

The objective of this work is to study the ageing state of a used reverse osmosis (RO) membrane taken in Algeria from the Benisaf Water Company seawater desalination unit. The study consists of an autopsy procedure used to perform a chain of analyses on a membrane sheet. Wear of the membrane is characterized by a degradation of its performance due to a significant increase in hydraulic permeability (25%) and pressure drop as well as a decrease in salt retention (10% to 30%). In most cases the effects of ageing are little or poorly known at the local level and global measurements such as (flux, transmembrane pressure, permeate flow, retention rate, etc.) do not allow characterization. Therefore, a used RO (reverse osmosis) membrane was selected at the site to perform the membrane autopsy tests. These tests make it possible to analyze and identify the cause as well as to understand the links between performance degradation observed at the macroscopic scale and at the scale at which ageing takes place. External and internal visual observations allow seeing the state of degradation. Microscopic analysis of the used membranes surface shows the importance of fouling. In addition, quantification and identification analyses determine a high fouling rate in the used membrane whose foulants is of inorganic and organic nature. Moreover, the analyses proved the presence of a biofilm composed of protein.

A rapid small scale evaluation of ultrafiltration performance for surface water treatment at Alcantarilha's water treatment works (Algarve, Portugal)

2004 ◽  
Vol 4 (5-6) ◽  
pp. 199-206
Author(s):  
M. Ribau Teixeira ◽  
H. Lucas ◽  
M.J. Rosa
Keyword(s):  
Water Treatment ◽  
Membrane Fouling ◽  
Conventional Treatment ◽  
Apparent Molecular Weight ◽  
Small Scale ◽  
Hydraulic Permeability ◽  
Scale Evaluation ◽  
Surface Water Treatment ◽  
Drinking Water Production ◽  
Pre Treatment

A rapid small-scale evaluation of ultrafiltration (UF) performance with and without physical–chemical pre-treatment was performed to up-grade the conventional treatment used for drinking water production in Alcantarilha's water treatment works, Algarve, Portugal. Direct UF and pre-ozonation/coagulation/flocculation/sedimentation/UF (O/C/F/S/UF) were evaluated using polysulphone membranes of different apparent molecular weight cut-off (MWCO) (15–47 kDa). The results indicated that (i) UF is an effective barrier against microorganisms, including virus larger than 80 nm; (ii) for surface waters with low to moderate SUVA values, direct UF performance is equivalent or better than the conventional treatment in terms of residual turbidity, while UV254 nm and TOC residuals require the use of O/C/F/S/UF; (iii) the permeate quality improves with the membrane apparent MWCO decrease, especially for the direct UF, although the conventional treatment performance is never reached using UF; (iv) membrane fouling and adsorption phenomena are more severe in direct UF than in O/C/F/S/UF sequence (pre-ozonation decreases the membrane foulants by decreasing their hydrophobicity) and these phenomena increase with the membrane hydraulic permeability and, particularly, with the membrane apparent MWCO.

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