Non-Isothermal Multi-Component Reactive Transport Model for Unsaturated Soil – Some Numerical Aspects

A multi-component reactive transport model, coupled to an existing thermal, hydraulic and mechanical model is investigated. The model is based on conservation of mass/energy principles for the flow and stress strain equilibrium for the mechanical behaviour. The resultant model is coupled to a geochemical model in order to capture geochemical interactions. Numerically, the Galerkin finite element method is employed for spatial discretisation and an implicit Euler method for temporal discretisation. The coupling between the transport and geochemical models is achieved via both non-iterative and iterative approaches. A series of applications are considered to demonstrate the numerical performance and qualitative behaviour, specifically in the context of multi-component behaviour. The model shows good stability, convergence and computational efficiency.