Simulation of mixing-limited reactions using a continuum approach

The limiting of reaction rates in porous media due to the imperfect mixing of reactants is a well studied phenomenon. It has been observed on both the field and laboratory scale and studied using a range of numerical techniques including continuum approaches and Lagrangian particle tracking methods. A new method is presented here for the simulation of mixing-limited reactions using continuum methods, based on the idea of separating each reactant into a mixed and an unmixed fraction, of which only the mixed fraction can react. The method is shown to be capable of producing mixing-limited reaction rates associated with one-, two-, and three-dimensional systems, and of producing outputs well fitted to the experimental data presented in Gramling et al. (2002) .