Approximations for Adapting Porous Media Radionuclide Transport Models to Analysis of Transport in Jointed, Porous Rock

1982 ◽  
Vol 15 ◽  
Author(s):  
K. L. Erickson
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Retardation Factor ◽  
Radionuclide Transport ◽  
Porous Rock ◽  
Transport Models ◽  
Porous Media Model

ABSTRACTInitial criteria are defined which determine when radionuclide transport in jointed, porous rock can be approximated as occurring in an equivalent porous medium. For systems satisfying those criteria, the retardation factor to be used in the equivalent porous media model also is defined.

A Comparative Analysis Of Fractured and Porous Medium Radionuclide Transport

1981 ◽  
Vol 11 ◽  
Author(s):  
B. J. Travis ◽  
H. E. Nuttall
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Comparative Analysis ◽  
Ion Transport ◽  
Radionuclide Transport ◽  
Fracture Frequency ◽  
The Usa ◽  
Nuclide Transport ◽  
Geological Formations

Modeling of radionuclide transport in geological formations has until recently been limited to the treatment of nonfractured porous media. Recently researchers in Sweden, Canada, France, and the USA have become interested in the problems of nuclide transport in geological formations which may contain fractures. Since many conventional porous-medium ion-transport codes are available, the question arises as to when fracture widths and fracture frequency dictate the use of these existing codes.

Improved Radionuclide Transport Models for a Nuclear Waste Repository

1995 ◽  
Vol 412 ◽  
Author(s):  
Richard B. Codell
Keyword(s):  
Porous Media ◽  
Fractured Porous Media ◽  
Nuclear Waste Repository ◽  
Hybrid Technique ◽  
Radionuclide Transport ◽  
Transport Models ◽  
The Status ◽  
The Time Domain ◽  
Chain Decay ◽  
Number Of Authors

AbstractNRC is developing improved models for transport of chain decay radionuclides in porous and fractured/porous media using finite-difference for spatial discretization, and numerical inversion of Laplace transforms for time. This hybrid technique allows great flexibility for spatial variability, flow rate changes and boundary conditions that are difficult with analytical solutions, and are much faster than solutions fully in the time domain. This paper presents the status of NRC's development of a method for transport through fractured porous media at the proposed Yucca Mountain repository, building on the work of a number of authors.

Critical radius of endotherms

1986 ◽  
Vol 250 (4) ◽  
pp. R699-R707
Author(s):  
W. P. Porter ◽  
D. F. Parkhurst ◽  
P. A. McClure
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Porous Media ◽  
Thermal Resistance ◽  
Critical Radius ◽  
Previous Analysis ◽  
Small Animals ◽  
Porous Media Model ◽  
Simultaneous Heat ◽  
Solid Insulation

The critical radius effect for insulation, well known in the engineering literature, was used by other authors to explain the lack of insulation on newborn endotherms. If that effect existed in small animals, they would lose less heat if nude than if fur or feathers were present. We show 1) that the previous analysis, although incomplete, yields the same result as a solid insulation model with the required sophistication and 2) that a proper model of fur is a porous media model. Neither of two porous media versions yield a critical radius effect. No critical radius effect occurs because simultaneous heat transfer by conduction and radiation makes it impossible to obtain the required logarithmic increase in thermal resistance with increasing insulation radius in a porous medium.

scholarly journals Leakage performance predictions of a brush seal based on fluid–solid coupling method

2020 ◽  
Vol 103 (1) ◽  
pp. 003685041989722
Author(s):  
Chang Yue ◽  
Sun Bitian ◽  
Zhang Lanzhu
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Boundary Conditions ◽  
Coupling Model ◽  
Calculation Model ◽  
Brush Seal ◽  
Sealing Performance ◽  
Performance Predictions ◽  
Porous Media Model ◽  
Porous Medium Model

The sealing performance of a brush seal is studied in this article. At present, the mostly used model to analyze the performance of a brush seal is porous medium model in which the effect of bristle deformation is not considered. Here, a combined numerical method is proposed. First, the deformation of bristle is calculated in a fluid–solid coupling model with a simplified bristle model, and then the results of the bristle deformation is imported to a porous media model as the boundary conditions. More accurate media flow and leakage variation law of the brush seal are obtained with this calculation model.

scholarly journals A “lab-on-a-chip” experiment for assessing mineral precipitation processes in fractured porous media

2020 ◽  
Author(s):  
Jenna Poonoosamy ◽  
Sophie Roman ◽  
Cyprien Soulaine ◽  
Hang Deng ◽  
Sergi Molins ◽  
...  
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Reactive Transport ◽  
Surface Passivation ◽  
Pore Scale ◽  
Mineral Precipitation ◽  
Transport Models ◽  
Mineral Transformation ◽  
Fractured Porous Medium ◽  
Fractured Medium

<p>The understanding of dissolution and precipitation of minerals and its impact on the transport of fluids in fractured media is essential for various subsurface applications including shale gas production using hydraulic fracturing (“fracking”), CO<sub>2</sub> sequestration, or geothermal energy extraction. The implementation of such coupled processes into numerical reactive transport codes requires a mechanistic process understanding and model validation with quantitative experiments. In this context, we developed a microfluidic “lab-on-chip” of a reactive fractured porous medium of 800 µm × 900 µm size with 10 µm depth. The fractured medium consisted of compacted celestine grains (grain size 4 – 9 µm). A BaCl<sub>2</sub> solution was injected into the microreactor at a flow rate of 500 nl min<sup>-1</sup>, leading to the dissolution of celestine and an epitaxial growth of barite on its surface (Poonoosamy et al., 2016). Our investigations including confocal Raman spectroscopic techniques allowed for monitoring the temporal mineral transformation at the pore scale in 2D and 3D geometries. The fractured porous medium causes a heterogeneous flow field in the microreactor that leads to spatially different mineral transformation rates. In these experiments, the dynamic evolution of surface passivation processes depends on two intertwined processes: i) the dissolution of the primary mineral that is needed for the subsequent precipitation, and ii) the suppression of the dissolution reaction as a result of secondary mineral precipitation. However, the description of evolving reactive surface areas to account for mineral passivation mechanisms in reactive transport models following Daval et al. (2009) showed several limitations, and prompt for an improved description of passivation processes that includes the diffusive properties of secondary phases (Poonoosamy et al., 2020). The results of the ongoing microfluidic experiments in combination with advanced pore-scale modelling will provide new insights regarding application and extension of the description of surface passivation processes to be included in (continuum-scale) reactive transport models.</p><p>Daval D., Martinez I., Corvisier J., Findling N., Goffé B. and Guyotac F. (2009) Carbonation of Ca-bearing silicates, the case of wollastonite: Experimental investigations and kinetic modelling. Chem. Geol. 265(1–2), 63-78.</p><p>Poonoosamy J., Curti E., Kosakowski G., Van Loon L. R., Grolimund D. and Mäder U. (2016) Barite precipitation following celestite dissolution in a porous medium: a SEM/BSE and micro XRF/XRD study. Geochim. Cosmochim. Acta 182, 131-144.</p><p>Poonoosamy J., Klinkenberg M., Deissmann G., Brandt F., Bosbach D., Mäder U. and Kosakowski G. (2020) Effects of solution supersaturation on barite precipitation in porous media and consequences on permeability: experiments and modelling. Geochim. Cosmochim. Acta 270, 43-60.</p>

Analysis of static sealing rules of foamed silicone rubber based on a porous media model

2019 ◽  
Vol 39 (3) ◽  
pp. 101-116
Author(s):  
Tianzheng Wen ◽  
Fei Guo ◽  
Yijie Huang ◽  
Shixing Zhu ◽  
Xiaohong Jia
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Contact Pressure ◽  
Silicone Rubber ◽  
Cell Structure ◽  
Cell Contact ◽  
Relative Pressure ◽  
Medium Model ◽  
Porous Media Model ◽  
Porous Medium Model

We established a method for calculating and analyzing the static leakage rate based on a porous media model for foamed silicone rubber materials. The mechanical properties of the foamed silicone rubber material under macroscopic compression were described by the Ogden third (foam) model in the finite-element hyperelastic model. It solved the problem of difficult convergence of large compressible and volume compressible cell materials. The size and distribution of the cells on the surface of the foamed material were obtained by a white-light interferometer and mathematical fitting. The boundary conditions for solving the porous medium model were obtained by the coupling of the macroscopic contact pressure and the microscopic cell contact pressure. For the unique cell structure and contact state of the surface of the foamed material, the flow state of the fluid at the sealing interface was described by a porous medium model, and the leak rate was obtained. In addition, this article analyzed the effect of different compression and the relative pressure of the sealing end face on the leakage.

Conservative solute transport with periodic velocity and sinusoidal source concentration in semi-infinite porous media: An analytical solution

2014 ◽  
Vol 6 (1) ◽  
pp. 1024-1031
Author(s):  
R R Yadav ◽  
Gulrana Gulrana ◽  
Dilip Kumar Jaiswal
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Laplace Transformation ◽  
Seepage Velocity ◽  
Transformation Technique ◽  
Numerical Examples ◽  
One Dimensional ◽  
Porous Domain ◽  
Conservative Solute Transport ◽  
Source Concentration

The present paper has been focused mainly towards understanding of the various parameters affecting the transport of conservative solutes in horizontally semi-infinite porous media. A model is presented for simulating one-dimensional transport of solute considering the porous medium to be homogeneous, isotropic and adsorbing nature under the influence of periodic seepage velocity. Initially the porous domain is not solute free. The solute is initially introduced from a sinusoidal point source. The transport equation is solved analytically by using Laplace Transformation Technique. Alternate as an illustration; solutions for the present problem are illustrated by numerical examples and graphs.

Capillary Imbibition Dynamics in Porous Media

2014 ◽  
Author(s):  
Swayamdipta Bhaduri ◽  
Pankaj Sahu ◽  
Siddhartha Das ◽  
Aloke Kumar ◽  
Sushanta K. Mitra
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Paper Strip ◽  
Capillary Imbibition ◽  
Flow Physics ◽  
Fundamental Understanding ◽  
Paper Based Microfluidics ◽  
To Come

The phenomenon of capillary imbibition through porous media is important both due to its applications in several disciplines as well as the involved fundamental flow physics in micro-nanoscales. In the present study, where a simple paper strip plays the role of a porous medium, we observe an extremely interesting and non-intuitive wicking or imbibition dynamics, through which we can separate water and dye particles by allowing the paper strip to come in contact with a dye solution. This result is extremely significant in the context of understanding paper-based microfluidics, and the manner in which the fundamental understanding of the capillary imbibition phenomenon in a porous medium can be used to devise a paper-based microfluidic separator.

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