Mesoscale modeling of brine processes in a single salt crystal

We present a pore-scale (mesoscale) model for simulating multiphase reactive transport processes including phase transition and dissolution/ precipitation. The model is based on the lattice Boltzmann method and combines the existing single-component multiphase model, the mass transport model, and the dissolution/precipitation model. Additional schemes are developed to handle reactive and moving boundaries with complex geometries, to account for liquid/vapor phase transition, and to guarantee mass and momentum conservation. The pore-scale model can capture coupled non-linear multiple physicochemical processes including multiphase flow with phase separation, heat transfer, mass transport, chemical reaction, dissolution/precipitation, and dynamic evolution of the pore geometries. After confirming the numerical implementation by comparing to other solutions of several multiphase flow and reactive transport problems, we use the model to study the behavior of a brine inclusion in a single salt crystal. Multiphase reactive transport phenomena with phase transition between liquid-vapor phases and dissolution/precipitation of the salt in the brine inclusion are simulated, and effects of initial inclusion size and temperature gradient on the brine behavior are investigated. Many experimental observations are reproduced.