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Transport of reacting solutes subject to a moving dissolution boundary: Numerical methods and solutions

Water Resources Research

By:
and
https://doi.org/10.1029/WR023i008p01561

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Abstract

A moving boundary problem which arises during transport with precipitation-dissolution reactions is solved by three different numerical methods. Two of these methods (one explicit and one implicit) are based on an integral formulation of mass balance and lead to an approximation of a weak solution. These methods are compared to a front-tracking scheme. Although the two approaches are conceptually different, the numerical solutions showed good agreement. As the ratio of dispersion to convection decreases, the methods based on the integral formulation become computationally more efficient. Specific reactions were modeled to examine the dependence of the system on the physical and chemical parameters. Although the water flow rate does not explicitly appear in the equation for the velocity of the moving boundary, the speed of the boundary depends more on the flux rate than on the dispersion coefficient. The discontinuity in the gradient of the solute concentration profile at the boundary increases with convection and with the initial concentration of the mineral. Our implicit method is extended to allow participation of the solutes in complexation reactions as well as the precipitation-dissolution reaction. This extension is easily made and does not change the basic method.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Transport of reacting solutes subject to a moving dissolution boundary: Numerical methods and solutions
Series title:
Water Resources Research
DOI:
10.1029/WR023i008p01561
Volume:
23
Issue:
8
Year Published:
1987
Language:
English
Publisher:
American Geophysical Union
Contributing office(s):
Toxic Substances Hydrology Program
Description:
14 p.
First page:
1561
Last page:
1574