scholarly journals Magnetic Resonance Velocimetry Measurement of Viscous Flows through Porous Media: Comparison with Simulation and Voxel Size Study

Physics ◽  
2021 ◽  
Vol 3 (4) ◽  
pp. 1254-1267
Author(s):  
Martin Bruschewski ◽  
Sam Flint ◽  
Sid Becker
Keyword(s):  
Porous Media ◽  
Magnetic Resonance ◽  
Measurement Uncertainty ◽  
Pore Size ◽  
Velocity Data ◽  
Voxel Size ◽  
3 Dimensional ◽  
Magnetic Resonance Velocimetry ◽  
Flows Through Porous Media ◽  
Good Agreement

Studies that use magnetic resonance velocimetry (MRV) to assess flows through porous media require a sufficiently small voxel size to determine the velocity field at a sub-pore scale. The smaller the voxel size, the less information is lost through the discretization. However, the measurement uncertainty and the measurement time are increased. Knowing the relationship between voxel size and measurement accuracy would help researchers select a voxel size that is not too small in order to avoid unnecessary measurement effort. This study presents a systematic parameter study with a low-Reynolds-number flow of a glycerol–water mixture sent through a regularly periodic porous matrix with a pore size of 5 mm. The matrix was a 3-dimensional polymer print, and velocity-encoded MRV measurements were made at 15 different voxel sizes between 0.42 mm and 4.48 mm. The baseline accuracy of the MRV velocity data was examined through a comparison with a computational fluid dynamics (CFD) simulation. The experiment and simulation show very good agreement, indicating a low measurement error. Starting from the smallest examined voxel size, the influence of the voxel size on the accuracy of the velocity data was then examined. This experiment enables us to conclude that a voxel size of 0.96 mm, which corresponds to 20% of the pore size, is sufficient. The volume-averaged results do not change below a voxel size of 20% of the pore size, whereas systematic deviations occur with larger voxels. The same trend is observed with the local velocity data. The streamlines calculated from the MRV velocity data are not influenced by the voxel size for voxels of up to 20% of the pore size, and even slightly larger voxels still show good agreement. In summary, this study shows that even with a relatively low measurement resolution, quantitative 3-dimensional velocity fields can be obtained through porous flow systems with short measurement times and low measurement uncertainty.

Estimation of the measurement uncertainty in magnetic resonance velocimetry based on statistical models

2016 ◽  
Vol 57 (5) ◽  
Author(s):  
Martin Bruschewski ◽  
Daniel Freudenhammer ◽  
Waltraud B. Buchenberg ◽  
Heinz-Peter Schiffer ◽  
Sven Grundmann
Keyword(s):  
Magnetic Resonance ◽  
Measurement Uncertainty ◽  
Statistical Models ◽  
Magnetic Resonance Velocimetry

Incompressible lattice Boltzmann model for axisymmetric flows through porous media

2015 ◽  
Vol 26 (04) ◽  
pp. 1550036 ◽  
Author(s):  
Fumei Rong ◽  
Baochang Shi
Keyword(s):  
Porous Media ◽  
Distribution Function ◽  
Lattice Boltzmann ◽  
Incompressible Flows ◽  
Lattice Boltzmann Model ◽  
Large Pressure ◽  
Flows Through Porous Media ◽  
Simple Processing ◽  
Boltzmann Model ◽  
Good Agreement

In this paper, an axisymmetric LBE model for incompressible flows through porous media is proposed. In this model, the influence of density change caused by large pressure difference can be overcome by replacing density distribution function with pressure distribution function. A more simple processing format for external force is introduced so as to make the involved method in this paper more perfect. The coupling between flow velocity and pressure also can be significantly reduced when calculating the macroscopic quantities. Good agreement between the analytical solution and numerical results is also obtained based on this model and it also can provide guidance for other problem with such complicated force forms.

Comparison of translabial three-dimensional ultrasonography and magnetic resonance imaging for the grading of levator ani defects

2021 ◽  
Author(s):  
Yijia Luo ◽  
Linxin Yang ◽  
Ning Lin ◽  
Zhihua Fan ◽  
Chenshan Dong
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Morphological Characteristics ◽  
Weighted Kappa ◽  
Levator Ani ◽  
Resonance Imaging ◽  
3 Dimensional ◽  
Moderate Agreement ◽  
Grading Systems ◽  
Good Agreement

Abstract Purpose: Levator ani defect (LAD) closely correlates with pelvic organ prolapse. This study aimed to compare the LAD grading between 3-dimensional ultrasonography (3D-US) and magnetic resonance imaging (MRI) and investigate the reasons for the difference using 3-dimensional pelvic models. Methods: Seventy-two Chinese women who were to undergo repair surgery were assessed by the prolapse staging, 3D-US and MRI. LAD was graded according to the grading systems described with regard to 3D-US (Dietz et al.) and MRI (Delancey et al.) The puborectalis attachment width and the puborectalis thickness were measured on the reconstructed pelvic models offline within the software. The results were analyzed using the weighted kappa and the ANOVA test. Results: The grading systems used for 3D-US and MRI showed the good agreement (k=0.75), whereas the consensus of the extent (ie, partial or complete) of tears showed the moderate agreement (k=0.56). Additionally, iliococcygeus tears detected by MRI (n=3) accompanied with complete puborectalis tears on the same side. The averaged width of intact puborectalis attachment was 13.75±3.43mm. The width of intact puborectalis attachment was remarkably higher than that of the injured attachment (P=.005). The averaged puborectalis thickness was 9.85±2.13mm. Conclusions: Comparison of 3D-US and MRI showed the good agreement on LAD grading. The moderate agreement in assessing partial or complete tears resulted from the grading criteria of 3D-US. The morphological characteristics of puborectalis assisted in identifying complete tears.

PREDICTION OF MAXIMUM PORE SIZE OF POROUS MEDIA BASED ON FRACTAL GEOMETRY

Fractals ◽  
2010 ◽  
Vol 18 (04) ◽  
pp. 417-423 ◽  
Author(s):  
JIANCHAO CAI ◽  
BOMING YU
Keyword(s):  
Porous Media ◽  
Pore Size ◽  
Transport Properties ◽  
Fractal Geometry ◽  
Science And Engineering ◽  
Porosity And Permeability ◽  
Maximum Pore Size ◽  
Analytical Expressions ◽  
Good Agreement

The macroscopic transport properties of porous media have received steadily attention in science and engineering areas in the past decades. It has been shown that the maximum pore size in a porous medium plays the crucial role in determination of transport properties such as flow resistance, permeability, thermal conductivity and electrical conductivity, etc. In this study, two models for predicting the maximum pore size in porous media based on fractal geometry are presented. The present analytical expressions may be used to calculate the maximum pore size from porosity and permeability data, as well as from liquid properties, structure parameters of media and imbibition coefficient data, respectively. Predicted maximum pore sizes by the proposed models show good agreement with the available experimental results.

scholarly journals CO2 Convective Dissolution in Oil-Saturated Unconsolidated Porous Media at Reservoir Conditions

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 233
Author(s):  
Widuramina Amarasinghe ◽  
Ingebret Fjelde ◽  
Nils Giske ◽  
Ying Guo
Keyword(s):  
Porous Media ◽  
Crude Oil ◽  
Water Solution ◽  
Co2 Storage ◽  
Bromothymol Blue ◽  
Power Relationship ◽  
Dimensionless Time ◽  
3 Dimensional ◽  
Reservoir Conditions ◽  
Unconsolidated Porous Media

During CO2 storage, CO2 plume mixes with the water and oil present at the reservoir, initiated by diffusion followed by a density gradient that leads to a convective flow. Studies are available where CO2 convective mixing have been studied in water phase but limited in oil phase. This study was conducted to reach this gap, and experiments were conducted in a vertically packed 3-dimensional column with oil-saturated unconsolidated porous media at 100 bar and 50 °C (representative of reservoir pressure and temperature conditions). N-Decane and crude oil were used as oils, and glass beads as porous media. A bromothymol blue water solution-filled sapphire cell connected at the bottom of the column was used to monitor the CO2 breakthrough. With the increase of the Rayleigh number, the CO2 transport rate in n-decane was found to increase as a function of a second order polynomial. Ra number vs. dimensionless time τ had a power relationship in the form of Ra = c×τ−n. The overall pressure decay was faster in n-decane compared to crude oil for similar permeability (4 D), and the crude oil had a breakthrough time three times slower than in n-decane. The results were compared with similar experiments that have been carried out using water.

Combined time-lapse magnetic resonance imaging and modeling to investigate colloid deposition and transport in porous media

2017 ◽  
Vol 123 ◽  
pp. 12-20 ◽  
Author(s):  
Alizée P. Lehoux ◽  
Pamela Faure ◽  
François Lafolie ◽  
Stéphane Rodts ◽  
Denis Courtier-Murias ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Porous Media ◽  
Magnetic Resonance ◽  
Time Lapse ◽  
Resonance Imaging ◽  
Transport In Porous Media ◽  
Colloid Deposition

Application of Low-Field Nuclear Magnetic Resonance (LFNMR) in Characterizing the Dissociation of Gas Hydrate in a Porous Media

2021 ◽  
Vol 35 (3) ◽  
pp. 2174-2182
Author(s):  
Yongchao Zhang ◽  
Lele Liu ◽  
Daigang Wang ◽  
Pengfei Chen ◽  
Zhun Zhang ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Porous Media ◽  
Magnetic Resonance ◽  
Gas Hydrate ◽  
Low Field ◽  
Nuclear Magnetic
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