Nonisothermal multicomponent reactive transport model for unsaturated soil

A multicomponent reactive transport model, coupled with an existing thermal, hydraulic, and mechanical model for porous media, is investigated. The model is based on conservation of mass/energy principles for the flow and stress-strain equilibrium for the mechanical behavior. The resultant model is coupled with a geochemical model to capture geochemical interactions. Numerically, the Galerkin FEM is employed for spatial discretization and an implicit Euler method for temporal discretization. The coupling of the transport and geochemical models is achieved through both noniterative and iterative approaches. A series of applications are considered to demonstrate the numerical performance and qualitative behavior, specifically in the context of multicomponent behavior. The model shows good convergence and computational efficiency