Numerical Simulation of Solute Transport Instantaneously Injected in a Single Rock Fracture System: Inclusion of a Nonlinear Sorption Term

1994 ◽  
Vol 353 ◽  
Author(s):  
Yoko Fujikawa ◽  
M. Fukui

AbstractThe effect of nonlinear Freundlich sorption isotherm on the transport of sorptive solute in a system of fracture and porous matrix was investigated through numerical simulation. To solve a set of partial differential equations of solute transport with nonlinear term, use of the Laplace transform Galerkin (LTG) technique was investigated. It was shown that the LTG method could be applied successfully to solve quasi-linearized transport equation. Sensitivity analysis showed that nonlinear sorption in porous matrix with order less than 1 increased the skewness of the breakthrough curve. The fitting of experimental effluent data using a transport model with nonlinear isotherms was also conducted.

2020 ◽  
Vol 59 (4) ◽  
pp. 2827-2838 ◽  
Author(s):  
Imtiaz Ahmad ◽  
Muhammad N. Khan ◽  
Mustafa Inc ◽  
Hijaz Ahmad ◽  
K.S. Nisar

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Jianli Shao ◽  
Qi Zhang ◽  
Wenbin Sun ◽  
Zaiyong Wang ◽  
Xianxiang Zhu

The influence of rock seepage must be considered in geotechnical engineering, and understanding the fluid flow in rock fractures is of great concern in the seepage effect investigation. This study is aimed at developing a model for inversion of rock fracture domains based on digital images and further study of non-Darcy flow. The visualization model of single rock fracture domain is realized by digital images, which is further used in flow numerical simulation. We further discuss the influence of fracture domain geometry on non-Darcy flow. The results show that it is feasible to study non-Darcy flow in rock fracture domains by inversion based on digital images. In addition, as the joint roughness coefficient (JRC) increases or the fracture aperture decreases, distortion of the fluid flow path increases, and the pressure gradient loss caused by the inertial force increases. Both coefficients of the Forchheimer equation decrease with increasing fracture aperture and increase with increasing JRC. Meanwhile, the critical Reynolds number tends to decrease when JRC increases or the fracture aperture decreases, indicating that the fluid tends to non-Darcy flow. This work provides a reference for the study of non-Darcy flow through rock fractures.


2010 ◽  
Vol 87 (2) ◽  
pp. 503-523 ◽  
Author(s):  
Victor Vilarrasa ◽  
Tomofumi Koyama ◽  
Ivars Neretnieks ◽  
Lanru Jing

2020 ◽  
Vol 18 (1) ◽  
pp. 232-238
Author(s):  
Zhihong Zhang ◽  
Gailei Tian ◽  
Lin Han

AbstractSolute transport through the clay liner is a significant process in many waste landfills or unmanaged landfills. At present, researchers mainly focus on the test study about semi-membrane property of clay material, however, the influence of chemical osmosis caused by membrane effect on solute transport and fluid velocity is insufficient. In this investigation, based on the classical advection-diffusion equation, a one-dimensional solute transport model for low-permeable clay material has been proposed, in which the coupled fluid velocity related with hydraulic gradient and concentration gradient is introduced, and the semi-membrane effect is embodied in the diffusion mechanism. The influence of chemical osmosis on fluid velocity and solute transport has been analyzed using COMSOL Multiphysics software. The simulated results show that chemical osmosis has a significant retarded action on fluid velocity and pollutant transport. The proposed model can effectively reveal the change in process of coupled fluid velocity under dual gradient and solute transport, which can provide a theoretical guidance for similar fluid movement in engineering.


1995 ◽  
Vol 412 ◽  
Author(s):  
A. V. Wolfsberg ◽  
B. A. Robinson ◽  
J. T. Fabryka-Martin

AbstractCharacterization and performance assessment (PA) studies for the potential high-level nuclear waste repository at Yucca Mountain require an understanding of migration mechanisms and pathways of radioactive solutes. Measurements of 36C1 in samples extracted from boreholes at the site are being used in conjunction with recent infiltration estimates to calibrate a site-scale flow and solute transport model. This exercise using the flow and solute transport model, FEHM, involves testing different model formulations and two different hypotheses to explain the occurrence of elevated 36Cl in the Calico Hills unit (CHn) which indicates younger water than in the overlying Topopah Spring unit (TSw). One hypothesis suggests fast vertical transport from the surface via fractures in the TSw to the CHn. An alternative hypothesis is that the elevated 36C1 concentrations reflect rapid horizontal flow in the CHn or at the interface between the CHn and the TSw with the source being vertical percolation under spatially isolated regions of high infiltration or at outcrops of those units. Arguments in favor of and against the hypotheses are described in conjunction with the site-scale transport studies.


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