scholarly journals Experimental and theoretical study of coupled influence of flow velocity increment and particle size on particle retention and release in porous media

2017 ◽  
Vol 10 (3) ◽  
pp. 236-245 ◽  
Author(s):  
Xing-xin Chen ◽  
Qi-peng Cai ◽  
Zhong-han Wu
Keyword(s):  
Particle Size ◽  
Porous Media ◽  
Flow Velocity ◽  
Theoretical Study ◽  
Velocity Increment ◽  
Particle Retention

scholarly journals The Hydrodynamic Dispersion Characteristics of Coral Sands

2019 ◽  
Vol 7 (9) ◽  
pp. 291 ◽  
Author(s):  
Xiang Cui ◽  
Changqi Zhu ◽  
Mingjian Hu ◽  
Xinzhi Wang ◽  
Haifeng Liu
Keyword(s):  
Particle Size ◽  
Porous Media ◽  
Flow Velocity ◽  
Molecular Diffusion ◽  
Dispersion Coefficient ◽  
Hydrodynamic Dispersion ◽  
Dispersion Characteristics ◽  
Factors Affecting ◽  
Mechanical Dispersion ◽  
Freshwater Aquifers

Dispersion characteristics are important factors affecting groundwater solute transport in porous media. In marine environments, solute dispersion leads to the formation of freshwater aquifers under islands. In this study, a series of model tests were designed to explore the relationship between the dispersion characteristics of solute in calcareous sands and the particle size, degree of compactness, and gradation of porous media, with a discussion of the types of dispersion mechanisms in coral sands. It was found that the particle size of coral sands was an important parameter affecting the dispersion coefficient, with the dispersion coefficient increasing with particle size. Gradation was also an important factor affecting the dispersion coefficient of coral sands, with the dispersion coefficient increasing with increasing d10. The dispersion coefficient of coral sands decreased approximately linearly with increasing compactness. The rate of decrease was −0.7244 for single-grained coral sands of particle size 0.25–0.5 mm. When the solute concentrations and particle sizes increased, the limiting concentration gradients at equilibrium decreased. In this study, based on the relative weights of molecular diffusion versus mechanical dispersion under different flow velocity conditions, the dispersion mechanisms were classified into five types, and for each type, a corresponding flow velocity limit was derived.

Mechanical Degradation of Polymers in Flows Through Porous Media: Effect of Flow Path Length and Particle Size

1997 ◽  
Vol 50 (11S) ◽  
pp. S149-S155 ◽  
Author(s):  
A. J. Mu¨ller ◽  
L. G. Patruyo ◽  
W. Montano ◽  
D. Roversi-M. ◽  
R. Moreno ◽  
...  
Keyword(s):  
Particle Size ◽  
Porous Medium ◽  
Porous Media ◽  
Flow Velocity ◽  
Path Length ◽  
Resistance Coefficient ◽  
Spherical Particles ◽  
Mechanical Degradation ◽  
Degradation Rates ◽  
Thickening Behavior

In this work, we present an experimental study of flow-induced degradation of hydrolyzed polyacrylamide in aqueous solutions flowing through porous media consisting of beds packed with monodisperse spherical particles. The degradation is analyzed by passing the solution repeatedly through the porous medium at a constant flow velocity, and then characterizing the degraded solution in terms of its resistance coefficient. Repeated passes through the porous medium are equivalent to increasing the path length of the solution. When the polyacrylamide is dissolved in deionized water, it exhibits a gradual extension thickening behavior in terms of increases in flow velocity. In this case, the polymer degrades as it passes through the porous medium, even at relatively low flow rates. When the polyacrylamide is dissolved in a NaCl solution, it exhibits critical extension thickening in porous media flows, and it only degrades at Reynolds numbers that are higher than the onset of the extension thickening behavior. With repeated passes, the polymer progressively degrades until an asymptotic value of resistance coefficient is reached. The results show that the effect of particle size on degradation rates depends on the basis used for comparison between experiments carried out in beds with different particle sizes. However, the degree of degradation achieved after long path lengths is always higher for the largest particle size employed under equivalent comparison parameters.

scholarly journals Waterfall Algorithm as a tool of investigation the geometrical features of granular porous media

2021 ◽  
Author(s):  
Wojciech Sobieski
Keyword(s):  
Particle Size ◽  
Porous Media ◽  
Lattice Boltzmann ◽  
Granular Media ◽  
Density Ratio ◽  
Geometrical Features ◽  
Granular Porous Media ◽  
Collision Density ◽  
Boltzmann Method ◽  
The Impact

AbstractThe paper describes the so-called Waterfall Algorithm, which may be used to calculate a set of parameters characterising the spatial structure of granular porous media, such as shift ratio, collision density ratio, consolidation ratio, path length and minimum tortuosity. The study is performed for 1800 different two-dimensional random pore structures. In each geometry, 100 individual paths are calculated. The impact of porosity and the particle size on the above-mentioned parameters is investigated. It was stated in the paper, that the minimum tortuosity calculated by the Waterfall Algorithm cannot be used directly as a representative tortuosity of pore channels in the Kozeny or the Carman meaning. However, it may be used indirect by making the assumption that a unambiguous relationship between the representative tortuosity and the minimum tortuosity exists. It was also stated, that the new parameters defined in the present study are sensitive on the porosity and the particle size and may be therefore applied as indicators of the geometry structure of granular media. The Waterfall Algorithm is compared with other methods of determining the tortuosity: A-Star Algorithm, Path Searching Algorithm, Random Walk technique, Path Tracking Method and the methodology of calculating the hydraulic tortuosity based on the Lattice Boltzmann Method. A very short calculation time is the main advantage of the Waterfall Algorithm, what meant, that it may be applied in a very large granular porous media.

Unsteady and porous media flow of reactive non-Newtonian fluids subjected to buoyancy and suction/injection

2015 ◽  
Vol 25 (7) ◽  
pp. 1682-1704 ◽  
Author(s):  
Tirivanhu Chinyoka ◽  
Daniel Oluwole Makinde
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Boundary Conditions ◽  
Flow Velocity ◽  
Flow System ◽  
Finite Difference Methods ◽  
Porous Media Flow ◽  
Convective Boundary Conditions ◽  
Convective Boundary ◽  
Content Type

Purpose – The purpose of this paper is to examine the unsteady pressure-driven flow of a reactive third-grade non-Newtonian fluid in a channel filled with a porous medium. The flow is subjected to buoyancy, suction/injection asymmetrical and convective boundary conditions. Design/methodology/approach – The authors assume that exothermic chemical reactions take place within the flow system and that the asymmetric convective heat exchange with the ambient at the surfaces follow Newton’s law of cooling. The authors also assume unidirectional suction injection flow of uniform strength across the channel. The flow system is modeled via coupled non-linear partial differential equations derived from conservation laws of physics. The flow velocity and temperature are obtained by solving the governing equations numerically using semi-implicit finite difference methods. Findings – The authors present the results graphically and draw qualitative and quantitative observations and conclusions with respect to various parameters embedded in the problem. In particular the authors make observations regarding the effects of bouyancy, convective boundary conditions, suction/injection, non-Newtonian character and reaction strength on the flow velocity, temperature, wall shear stress and wall heat transfer. Originality/value – The combined fluid dynamical, porous media and heat transfer effects investigated in this paper have to the authors’ knowledge not been studied. Such fluid dynamical problems find important application in petroleum recovery.

Experimental and Theoretical Study of Polymer Flow in Porous Media

1987 ◽  
Vol 2 (03) ◽  
pp. 281-304 ◽  
Author(s):  
K.S. Sorbie ◽  
A. Parker ◽  
P.J. Clifford
Keyword(s):  
Porous Media ◽  
Theoretical Study ◽  
Flow In Porous Media ◽  
Polymer Flow

Theoretical study of nematic to smectic transition in cylindrical porous media

2017 ◽  
Vol 45 (4) ◽  
pp. 574-578
Author(s):  
Kumari Jayanti Banerjee ◽  
A. S. Govind
Keyword(s):  
Porous Media ◽  
Theoretical Study

scholarly journals An experimental study on the determination of dispersion coefficient in layered soils

2021 ◽  
Author(s):  
Hamed Mahdipanah ◽  
Askari Tashakori ◽  
Samad Emamgholizadeh ◽  
Eisa Maroufpoor
Keyword(s):  
Porous Media ◽  
Flow Velocity ◽  
Sampling Method ◽  
Travel Distance ◽  
Coarse Grained ◽  
Contaminant Concentration ◽  
Fine Grained ◽  
Sodium Chloride Solutions ◽  
Heterogeneous Soils ◽  
Homogeneous Soil

Abstract Dispersivity is a measurable parameter in soil porous media that is used for studying the transport of contaminants to groundwater. The value of this parameter depends on various factors, including the kind of porous media (homogeneous or heterogeneous), flow velocity, initial contaminant concentration, travel distance, and sampling method. A physical model with dimensions of 0.10 m in width, 0.80 m in height, and 1.10 m in length was constructed to investigate the effects of these parameters on the dispersivity value. The stratified soil consisted of three 20-cm-thick layers containing fine-grained, medium-grained, and coarse-grained soil. Sodium chloride solutions with electrical conductivity values of 10, 14, and 19 dS/m were used as the contaminants. Flow was forced through the layered heterogeneous soils at three discharge velocities of 17.58, 22.02, and 26.18 × 10−5 m/s. The point and mixed sampling methods were used. The results indicated that the soil dispersivity values in the layered heterogeneous soils and homogeneous soil were influenced by contaminant concentration, flow velocity, and travel distance. Moreover, the dispersivity values obtained by point sampling were lower than those obtained using the mixed sampling method, and the mean dispersivity value in the layered heterogeneous soils was lower than that of the homogeneous soil.

Sign in / Sign up

Export Citation Format

Share Document