Experimental and Numerical Studies of Gas Permeability through Orthogonal Networks for Isotropic Porous Material

Grzegorz Wałowski

doi:10.3390/ma14143832

Experimental and Numerical Studies of Gas Permeability through Orthogonal Networks for Isotropic Porous Material

Materials ◽

10.3390/ma14143832 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3832

Author(s):

Grzegorz Wałowski

Keyword(s):

Porous Material ◽

Flow Resistance ◽

Gas Flow ◽

Gas Permeability ◽

Flow Direction ◽

Experimental Tests ◽

Simulation Method ◽

Spherical Particles ◽

Gas Velocity ◽

Permeability Characteristics

With regard to the problem of gas flow through isotropic porous deposits, the issues were considered in the category of description of gas movement mechanisms for structural models of the skeleton. As part of experimental tests of gas permeability through porous material in the form of polyamide, the numerical simulation method was used, using the k–ε turbulence model. The analysis of hydrodynamic phenomena occurring in the porous material made it possible to confront experimental research with numerical calculations. The analysis shows that, for a porous polyamide bed, there is a certain limit range of gas velocity (10−4–1) ms−1 at which flow resistance is the lowest. On the other hand, the highest value of the flow resistance is gradually achieved in the range of gas velocity (1–10) ms−1. This is due to the different structure of the isotropic polyamide material. The validation of the numerical model with experimental data indicates the validity of the adopted research methodology. It was found that the permeability characteristics of the tested porous material practically did not depend on the direction of gas flow. For porous polyamide, the permeability characteristic is non-linear, which, from the point of view of the measurements carried out, indicates the advantage of turbulent gas flow over its laminar movement. The novelty of the article is a proprietary method of measuring gas permeability for a cube-shaped sample made of a material constituting a sinter of spherical particles of equal dimensions. The method enables the determination of gas flow (in each flow direction) in microchannels forming an orthogonal network, characteristic of isotropic materials.

Download Full-text

Experimental Assessment of Porous Material Anisotropy and its Effect on Gas Permeability

Civil Engineering Journal ◽

10.28991/cej-0309143 ◽

2018 ◽

Vol 4 (4) ◽

pp. 906 ◽

Cited By ~ 1

Author(s):

Grzegorz Wałowski

Keyword(s):

Porous Material ◽

Gas Flow ◽

Gas Permeability ◽

Flow Direction ◽

Clean Energy ◽

Gas Production ◽

Material Anisotropy ◽

Internal Structures ◽

Flow Through ◽

New Generation

The results of experimental research upon the assessment of porous material anisotropy and its effect on gas permeability of porous materials with respect to the gas flow. The conducted research applied to natural materials with an anisotropic gap-porous structure and - for comparative purposes - to model materials such as coke, pumice and polyamide agglomerates. The research was conducted with the use of a special test stand that enables measuring the gas permeability with respect to three flow orientations compared with symmetric cubic-shaped samples. The research results show an explicit impact of the flow direction on the permeability of materials porous, which results from their anisotropic internal structures. The anisotropy coefficient and permeability effective coefficient of such materials was determined and an experimental evaluation of the value of this coefficient was conducted with respect to the gas stream and the total pressure drop across the porous deposit. The process of gas permeability was considered in the category of hydrodynamics of gas flow through porous deposits. It is important to broaden the knowledge of gas hydrodynamics assessment in porous media so far unrecognised for the development of a new generation of clean energy sources, especially in the context of biogas or raw gas production.

Download Full-text

Gas Permeability Model for Porous Materials from Underground Coal Gasification Technology

Energies ◽

10.3390/en14154462 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4462

Author(s):

Grzegorz Wałowski

Keyword(s):

Reynolds Number ◽

Flow Resistance ◽

Gas Flow ◽

Coal Gasification ◽

Gas Permeability ◽

Resistance Coefficient ◽

Underground Coal Gasification ◽

Permeability Model ◽

Permeability Characteristics

Underground coal gasification (UCG) technology converts deep coal resources into synthesis gas for use in the production of electricity, fuels and chemicals. This study provides an overview of the systematic methods of the in situ coal gasification process. Furthermore, the model of the porous structure of coal has been presented and the gas movement taking place in the carbon matrix—which is part of the bed—has been described. The experimental tests were carried out with the use of air forced through the nozzle in the form of a gas stream spreading in many directions in a porous bed under bubbling conditions. The gas flow resistance coefficient was determined as a function of the Reynolds number in relation to the diameter of the gas flow nozzle. The proprietary calculation model was compared to the models of many researchers, indicating a characteristic trend of a decrease in the gas flow resistance coefficient with an increase in Reynolds number. The novelty of the study is the determination of the permeability characteristics of char (carbonizate) in situ in relation to melted waste rock in situ, taking into account the tortuosity and gas permeability factors for an irregularly shaped solid.

Download Full-text

Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Anisotropic Skeletal Structure

10.20944/preprints201810.0132.v1 ◽

2018 ◽

Author(s):

Grzegorz Wałowski

Keyword(s):

Pressure Drop ◽

Porous Material ◽

Porous Materials ◽

Total Pressure ◽

Flow Resistance ◽

Gas Flow ◽

Gas Permeability ◽

Measuring System ◽

Skeletal Structure ◽

Total Pressure Drop

The hydrodynamic results obtained from the permeability of porous materials not only affect the assessment of the stream of the gas flow through those materials but they also refer to the loss of pressure energy in that flow. The direct measure of that loss is flow resistances.The results of experimental research upon the assessment of the flow resistances of porous materials with respect to gas flow. The research conducted applied to natural materials with an anisotropic gap-porous structure. The tests were carried out on a gas permeability measuring system, adapted to different shapes of porous material samples. The process issue of the total pressure drop on a porous deposit was considered in the Reynolds number category. The coefficient of flow resistance for anisotropic materials was defined and the value of this coefficient was compared to the gas stream and the total pressure drop on the porous bed was experimentally evaluated.

Download Full-text

Model of Flow Resistance Coefficient for a Fragment of a Porous Material Deposit with Skeletal Structure

Energies ◽

10.3390/en14113355 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3355

Author(s):

Grzegorz Wałowski

Keyword(s):

Pressure Drop ◽

Porous Material ◽

Total Pressure ◽

Flow Resistance ◽

Gas Flow ◽

Gas Permeability ◽

Resistance Coefficient ◽

Skeletal Structure ◽

Porous Bed ◽

Total Pressure Drop

The hydrodynamic conditions resulting from the permeability of porous materials are based not only on the assessment of the gas flow through these materials, but also the losses related to the pressure energy in this flow. Flow resistance is a direct measure of this loss. The aim of this experimental research was to evaluate the flow resistance of the porous material in relation to the gas flow. The research was carried out on a material with a slit-porous structure. The tests were carried out on a system for measuring gas permeability under the conditions of gas bubbling through the char. The issue of the total pressure drop process in the porous bed was considered in the Reynolds number category. The coefficient of flow resistance for the char was determined and the value of this coefficient was compared with the gas stream, and an experimental evaluation of the total pressure drop on the porous bed was made. The novelty of this article is the determination of the tortuosity and the gas permeability coefficient for a solid of any shape—a rigid skeleton.

Download Full-text

The UGKS Simulation of Microchannel Gas Flow and Heat Transfer Confined Between Isothermal and Nonisothermal Parallel Plates

Journal of Heat Transfer ◽

10.1115/1.4048255 ◽

2020 ◽

Vol 142 (12) ◽

Author(s):

Lianfu Dai ◽

Huiying Wu ◽

Jun Tang

Keyword(s):

Heat Transfer ◽

Cross Section ◽

Gas Flow ◽

Flow Direction ◽

Channel Height ◽

Parallel Plates ◽

Gas Temperature ◽

Gas Velocity ◽

Microscopic Mechanism ◽

Flow And Heat Transfer

Abstract The unified gas kinetic scheme (UGKS) is introduced to simulate the near transition regime gas flow and heat transfer in microchannel confined between isothermal and nonisothermal parallel plates. The argon gas is used and its inlet Knudsen number (Knin) ranges from 0.0154 to 0.0715. It is found that: (1) both microchannel gas flows under isothermal and nonisothermal parallel plates display a trend of speed acceleration and temperature decrease along flow direction, for which the microscopic mechanism explanation is first proposed; (2) inlet gas streamlines under nonisothermal plates condition deviate from the parallel distributions under isothermal plates condition due to the dual driving effects of pressure drop along flow direction and temperature difference along cross section; (3) gas temperature, pressure, density and viscosity distributions along cross section under nonisothermal plates condition deviate from the parabolic distributions under isothermal plates condition, while the gas velocity keeps the parabolic distribution due to the effect of Knudsen layer; (4) as channel height increases or channel length and gas molecular mean free path decrease, the gas temperature distribution along cross section under nonisothermal plates condition tends to transition from linear to curve one due to the decreasing effect of heat transfer along cross section and increasing effect of gas acceleration along flow direction, this transition from linear to curve one becomes more obvious along flow direction. (5) the gas velocity under nonisothermal plates condition decreases with the increase of inlet gas temperature (Tin), lower plate temperature (Tl) and Knin, while the gas temperature increases with the increase of Tin, Tl and Knin.

Download Full-text

Gas Flow Resistance Measurements Through Packed Beds at High Reynolds Numbers

Journal of Fluids Engineering ◽

10.1115/1.3240959 ◽

1983 ◽

Vol 105 (2) ◽

pp. 168-172 ◽

Cited By ~ 28

Author(s):

D. P. Jones ◽

H. Krier

Keyword(s):

Flow Resistance ◽

Gas Flow ◽

Test Chamber ◽

Particle Diameter ◽

Reynolds Numbers ◽

Spherical Particles ◽

Test Facility ◽

Packed Beds ◽

High Reynolds Numbers ◽

High Reynolds

This research study indicates that the classical Reynolds number dependency of the coefficient of drag for gases forced into packed beds is not correct at high Reynolds numbers. Care must also be taken to account for boundary layer wall effects that occur when the ratio of test chamber diameter to bead particle diameter is too small. Included is a review of the literature pertaining to gaseous flow resistance in packed beds. An existing test facility used in a previous study was found unsatisfactory, and necessary corrections were made to obtain normalized pressure gradient measurements at increasingly high Reynolds numbers. The resultant data was organized into a new correlation for the coefficient of drag, that is Fv=150+3.89Re1−φ0.87 This formula was developed for air flowing over spherical particles at Reynolds numbers ranging from 103–105.

Download Full-text

Influence of the Bed Type on the Flow Resistance Change During the Two-Phase (Gas + Powder) Flow through the Descending Packed Bed

Archives of Metallurgy and Materials ◽

10.2478/amm-2014-0135 ◽

2014 ◽

Vol 59 (2) ◽

pp. 795-800 ◽

Cited By ~ 2

Author(s):

B. Panic

Keyword(s):

Blast Furnace ◽

Physical Model ◽

Iron Powder ◽

Surface Properties ◽

Flow Resistance ◽

Gas Flow ◽

Chemical Processes ◽

Powder Flow ◽

Gas Velocity ◽

Powder System

Abstract The flow of gases with powder in the countercurrent to the charge materials occurs in many chemical processes. In the shaft metallurgical devices, the physical and chemical processes take place also in the countercurrent system. An important issue is that there are no disruptions of the flow in this multiphase system. Under real operating conditions of the device, the powder is generated within the process and its source is the charge or it is inserted to the device within the process procedure. In this system, a problem of bed particle suspension appears. That is why the author undertook investigations on the gas - powder flow in the descending bed. A physical model of this system was constructed. The experiments were performed and the influence of gas velocity, a type and size of the bed and powder particles as well as the powder concentration in the gas was established. Conditions when the descending bed suspension occurs were defined. In the case of physical model with glass materials, the suspension of bed did not occur. Therefore, investigations using beds of high alumina materials, blast furnace pellets and iron powder were performed. The results are presented below. When the bed of glass spheres was replaced with the bed of alumina spheres, a considerable increase in the volume of powder held up in the bed the gas flow resistance were observed. The surface properties of bed particles changed and better conditions for powder holdup were created. The actual gas velocity in the bed increased due to void fraction reduction. Replacement of the glass powder with the iron powder caused a change in the powder density, its surface properties and the shape factor. Greater amounts of the iron powder were held up in the bed and the gas flow resistance increased. Comparing the alumina particle bed - iron powder system to the blast furnace pellet bed - iron powder system, changes in the surface properties of bed particles and the void fraction of bed changed. The study results were the basis for defining conditions of the descending bed suspension.

Download Full-text

Lung volume, pressure, flow, and density relationships during constant-flow ventilation in dogs

Journal of Applied Physiology ◽

10.1152/jappl.1993.74.1.197 ◽

1993 ◽

Vol 74 (1) ◽

pp. 197-202 ◽

Cited By ~ 3

Author(s):

W. Brampton ◽

J. D. Young

Keyword(s):

Lung Volume ◽

Flow Resistance ◽

Gas Flow ◽

Gas Jet ◽

Constant Flow ◽

Airway Wall ◽

Gas Velocity ◽

Outflow Resistance ◽

Volume Changes ◽

Laminar And Turbulent Flow

Lung volume changes during constant-flow ventilation (CFV) using cannulas in the main stem bronchi were examined in six beagle dogs. The increase in lung volume was found to depend mainly on the outflow resistance to gas flow in the trachea and tracheal tube. The resistance changed with gas flow, indicating that gas flow was transitional between laminar and turbulent flow (resistance varies; is directly proportional to flow1.5). There was a small pressure gradient between trachea and alveoli (1.1–1.3 cmH2O) that was independent of flow rate or gas velocity out of the CFV cannulas. This was attributed to momentum transfer from the gas jet from the CFV cannulas modified by friction between the gas jet and the airway wall.

Download Full-text