Periodic Reporting for period 3 - ReactiveFronts (Mixing interfaces as reactive hotspots of porous media flows: theoretical upscaling, experimental imaging and field scale validation)
Reporting period: 2018-10-01 to 2020-03-31
The objective of the ReactiveFronts project is to address this knowledge gap by setting up a high level interdisciplinary team that will provide a new theoretical understanding and novel experimental imaging capacities for micro-scale interactions between flow, mixing and reactions and their impact on reactive front kinetics at the system scale. ReactiveFronts develops an original approach to this long-standing problem; combining theoretical, laboratory and field experimental methods.The focus on reactive interface dynamics, which represents a paradigm shift for reactive transport modelling in porous media, requires the development of original theoretical approaches (WP1) and novel milli-microfluidic experiments (WP2). This forms a basis for the study of complex features at increasing spatial scales, including the coupling between fluid dynamics and biological activity (WP4), the impact of 3D flow topologies and chaotic mixing on effective reaction kinetics (WP3), and the field scale assessment of these interactions (WP5).
Upscaling of the impact of these microscale processes on field scale phenomena will be achieved through the reactive lamella theory (Le Borgne et al., GRL 2014 JFM 2015, 2017). While simulations of reactive and microbiological processes in porous media and turbulent flow generally require weeks of computer time and allow only limited analysis of the governing equations, the new mechanistic model that we have introduced breaks down the complex three-dimensional coupling between mixing and biogeochemical processes into a reduced-dimension equation, allowing fast simulations and facilitating fundamental understanding. This will enable to link these microscale interactions to field scale processes, including redox and rock dissolution processes in the critical zone (PhD thesis Charlotte Le Traon), deep microbial hot spot development (Bochet et al., under review in nature geoscience) and bioclogging processes in geothermal operations (collaboration with Antea group).