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| Titel |
Invariantly propagating dissolution fingers in finite-width systems |
| VerfasserIn |
Filip Dutka, Piotr Szymczak |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121580
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| Publikation (Nr.) |
 EGU/EGU2016-356.pdf |
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| Zusammenfassung |
| Dissolution fingers are formed in porous medium due to positive feedback between transport
of reactant and chemical reactions [1-4]. We investigate two-dimensional semi-infinite
systems, with constant width W in one direction. In numerical simulations we solve the
Darcy flow problem combined with advection-dispersion-reaction equation for the solute
transport to track the evolving shapes of the fingers and concentration of reactant in the
system.
We find the stationary, invariantly propagating finger shapes for different widths of the
system, flow and reaction rates. Shape of the reaction front, turns out to be controlled by two
dimensionless numbers – the (width-based) Péclet number PeW = vW∕Dφ0 and Damköhler
number DaW = ksW∕v, where k is the reaction rate, s – specific reactive surface area, v -
characteristic flow rate, D – diffusion coefficient of the solute, and φ0 – initial porosity of the
rock matrix.
Depending on PeW and DaW stationary shapes can be divided into seperate classes, e.g.
parabolic-like and needle-like structures, which can be inferred from theoretical predictions.
In addition we determine velocity of propagating fingers in time and concentration of
reagent in the system. Our simulations are compared with natural forms (solution
pipes).
P. Ortoleva, J. Chadam, E. Merino, and A. Sen, Geochemical self-organization
II: the reactive-infiltration instability, Am. J. Sci, 287, 1008-1040 (1987).
M. L. Hoefner, and H. S. Fogler. Pore evolution and channel formation during
flow and reaction in porous media, AIChE Journal 34, 45-54 (1988).
C. E. Cohen, D. Ding, M. Quintard, and B. Bazin, From pore scale to wellbore
scale: impact of geometry on wormhole growth in carbonate acidization,
Chemical Engineering Science 63, 3088-3099 (2008).
P. Szymczak and A. J. C. Ladd, Reactive-infiltration nstabilities in rocks. Part II:
Dissolution of a porous matrix, J. Fluid Mech. 738, 591-630 (2014). |
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