V International Conference on Computational Methods for Coupled Problems in Science and Engineering COUPLED PROBLEMS 2013 S. Idelsohn, M. Papadrakakis and B. Schrefler (Eds) 1 LATTICE BOLTZMANN BASED MULTICOMPONENT REACTIVE TRANSPORT MODEL COUPLED WITH GEOCHEMICAL SOLVER FOR PORE SCALE SIMULATIONS RAVI A. PATEL †, ‡, * , JANEZ PERKO † , DIEDERIK JACQUES † , GEERT DE SCHUTTER ‡ , GUANG YE ‡, # , AND KLAAS VAN BREUGEL # † Belgium nuclear research center (SCK•CEN) Mol, Belgium. Email: rpatel@sckcen.be, Web page: http://www.sckcen.be ‡ Magnel lab for concrete research Ghent University Ghent, Belgium. Email: rapatel@ugent.be, Web page: http://www.ugent.be/ea/labomagnel/en # Microlab Delft University of Technology Delft, Netherlands. Email: K.vanBreugel@tudelft.nl, Web page: http://www.microlab.citg.tudelft.nl/ Key words: Lattice Boltzmann Method, reactive transport, pore scale modelling, geochemistry, PHREEQC coupling Abstract. A Lattice Boltzmann (LB) based reactive transport model intended to capture reactions and solid phase changes occurring at the pore scale is presented. The proposed approach uses LB method to compute multi component mass transport. The LB multi- component transport model is then coupled with the well-established geochemical reaction code PHREEQC which solves for thermodynamic equilibrium in mixed aqueous-solid phase system with homogenous and heterogeneous reactions. This coupling enables us to update solid phases volumes based on dissolution or precipitation using static update rules which, on pore scale, affects the change of potentially pore network geometry. Unlike conventional approach, heterogeneous reactions are conceptualized as volumetric reactions by introducing additional source term in the fluid node next to solid node, and not as flux boundaries. To demonstrate the validity of this approach several examples are presented in this paper. 1 INTRODUCTION Multicomponent reactive transport modelling is an important tool for analysing different applications involving coupled physical-chemical processes such as chemical degradation of cementitious materials, transport and sorption of radionuclides, environmental contaminant transport, bioremediation and geologic sequestration of carbon dioxide. Advancements in geochemical reaction modelling and reactive transport modelling have led to development of