Numerical modelling of reactive chemical transport under multiphase systems

In this paper, a numerical model, is presented for modelling reactive chemical transport under non-isothermal multiphase flow systems. The model is a coupled hydrologic transport and biogeochemical reaction code, which is used to predict the spatio-temporal distributions of all the important chemical species. To reduce primary dependent variables (PDVs), Gauss-Jordan decomposition is applied to the governing matrix equations for transport, resulting in mobile components and mobile kinetic variables as PDVs. Methods for coupling reaction and transport, such as sequential iteration approach (SIA) and predictor corrector approach are incorporated into the code to make the model versatile. Weak coupling will be applied to solve a system of chemical transport and heat transfer to save computing resources. The model developed is a practical tool for assessing migration of subsurface contamination and proper designing of remediation technologies. Examples are presented to demonstrate the application of the new model.