Pore-scale modeling of multiphase reactive transport with phase transitions and dissolution-precipitation processes in closed systems
Li Chen, Qinjun Kang, Bruce A. Robinson, Ya-Ling He, and Wen-Quan Tao
Accepted
A pore-scale model based on the lattice Boltzmann method (LBM) is developed for multiphase reactive transport with phase transition and dissolution/precipitation. The model combines the single-component multiphase Shan-Chen LB model [Phys. Rev. E 47, 1815 (1993)], the mass transport LB model [Chem. Eng. Sci. 60, 3405 (2005)] and the dissolution/precipitation model [J. Geophys. Res. 111, B05203 (2006)]. Care is taken to handle information on computational nodes undergoing solid/liquid or liquid/vapor phase changes to guarantee mass and momentum conservation. A new general LB concentration boundary condition is proposed that can handle various concentration boundaries including reactive and moving boundaries with complex geometries. The pore-scale model can capture coupled non-linear multiple physicochemical processes including multiphase flow with phase separation, mass transport, chemical reaction, dissolution/precipitation, and dynamic evolution of the pore geometries. The model is validated using several multiphase flow and reactive transport problems and then is used to study the thermal migration of a brine inclusion in a salt crystal. Multiphase reactive transport phenomena with phase transition between liquid-vapor phases and dissolution/precipitation of the salt in the closed inclusion are simulated, and the effects of initial inclusion size and temperature gradient on the thermal migration are investigated.