Simulation of Gravitational Instability During CO2 Absorption in a NaHCO3/Na2CO3 Solution

C. Wylock[1], A. Rednikov[1], B. Haut[1], P. Colinet[1]
[1]Université Libre de Bruxelles (ULB), Transfers, Interfaces and Processes (TIPs), Brussels, Belgium
Publié en 2013

This work deals with the modeling and the numerical simulation of the CO2 absorption, coupled with a chemical reaction, in an initially quiescent aqueous solution of sodium carbonate (Na2CO3) and bicarbonate (NaHCO3), inside a Hele-Shaw cell. In our Hele-Shaw cell, the liquid fills partially the gap between two parallel transparent Plexiglas plates. CO2 is forced to flow above the liquid in the cell and, therefore, it is absorbed in the liquid. It is observed experimentally, by interferometry, that this absorption, initially driven by diffusion and reaction, leads to the apparition of a gravitational instability. Assuming that this instability is triggered by a Rayleigh-Taylor mechanism, a two-dimensional model, coupling diffusion, chemical reaction and free convection, is proposed to simulate the development of the instability.

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