Open Access

ARTICLE

Solute Removal Analysis of a Large-scale Fracture Plane Considering Different Flow Paths and Different Hydraulic Head Differences

Qian Yin^1,2, Xiaojing Li^3,*, Liyuan Yu¹, Ming He¹, Richeng Liu^1,2

1 State Key Laboratory for Geomechanics & Deep Underground Engineering, China University of Mining and Technology, Xuzhou, 221116, China
2 School of Engineering, Nagasaki University, Nagasaki, Japan
3 School of Civil Engineering, Shandong Jianzhu University, Jinan, 116024, China

* Corresponding Author: Xiaojing Li. Email:

(This article belongs to the Special Issue: Modeling and Simulation of Fluid flows in Fractured Porous Media: Current Trends and Prospects)

Computer Modeling in Engineering & Sciences 2020, 124(1), 345-373. https://doi.org/10.32604/cmes.2020.08204

Received 06 August 2019; Accepted 16 March 2020; Issue published 19 June 2020

Abstract

An experimental and numerical study was carried out to investigate the solute removal process through a large-scale fracture plane considering different flow paths and hydraulic head differences. The visualization techniques were utilized in the experiment to capture the removal process images, which were then transferred to binary images. The variations in dimensionless concentration, which is defined as saturation of solute phase, were analyzed. With increasing hydraulic head difference, the speed of solute removal increases and the dimensionless concentration decreases. The flow paths result in different solute distribution patterns and different mechanisms for solute removal such as advection and diffusion, thus the curves of dimensionless concentration versus time are different. The dimensionless concentration over time decreases from approximately 1, which is smaller than 1 due to the existence of bubbles, to approximately 0, which is larger than 0 because the folds of the background are dealt as “solute”. A significant longer time is needed to achieve a certain fixed dimensionless concentration for a smaller hydraulic head difference. With the finite element software COMSOL multiphysics, the solute removal process, flow velocity fields, flow streamlines, as well as the hydraulic pressure fields were analyzed, which shows a good consistency with the experimental results. In practical engineering, when the solute pollutes the underground environment, the removal ability can be more significantly enforced by immediately applying a larger hydraulic head difference along a longer distance between the inlet and outlet boundaries.

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Keywords

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