Speaker
Description
Multiphase immiscible flows in porous media, involving phase exchange and/or chemical reaction are central to many chemical-engineering and environmental systems, including reactors, (catalytic) distillation, aquifer remediation, and more recently green-roof substrates. However, predictive simulation remains challenging because mechanistic models that consistently connect pore-scale transport and reaction within porous layers to an adjacent free-flow region are still limited. This work develops a multiscale, upscaled transport formulation for a surface reactive zone, where a porous media layer alternates with a neighboring free flow. Using the Method of Volume Averaging, the approach yields a yield to a single-domain model that explicitly represents the porous medium, containing liquid and vapor, a neighboring free-flow layer, and an inter-region that captures their mutual interaction. multicomponent species transport occurs in both phases, while a first-order heterogeneous reaction takes place on the solid–liquid surface. At the liquid–vapor interface, multicomponent phase exchange is modeled through a linear equilibrium relation analogous to Raoult’s law, using a partition coefficient. Under isothermal, quasi-steady assumptions, transport can be treated without resolving full hydrodynamics in detail, in essence of decoupling of momentum and balance equations. Starting from the local conservation equations, closed Generalized Transport Equations for multicomponent, multiphase mass transport with surface reaction are derived for the vicinity of the porous media layer–free layer interface. These equations contain effective tensors and convective-like terms that embody dispersion and co-dispersion induced by the microstructure, the phase distribution and the imposed flow. The effective properties are explicitly position-dependent, varying from the interior of the porous media layer across the inter-region and into the free layer, thereby capturing the gradual change in transport behavior near the interface. To determine such coefficients, steady, periodic closure problems are formulated on representative unit cells and solved numerically using the finite-element method, ensuring mesh-independent solutions. The parameter space is analyzed in terms of relevant dimensionless groups, including Péclet numbers for each phase and a Damköhler number for the surface reaction, allowing a compact interpretation of regimes dominated by convection, diffusion or reaction. Results show that the effective dispersion coefficients, evaporation rates and interfacial mass-transfer contributions exhibit strong spatial variations within the inter-region and a pronounced sensitivity to the equilibrium partition parameter. These trends highlight the key role of thermodynamics and local phase arrangement in controlling mass transport at the boundary between the porous media and free layers. The predictive capability of the upscaled formulation is evaluated by comparison with detailed pore-scale simulations of the concentration fields, yielding very good agreement in both the catalytic interior and the transfer region, with only moderate deviations confined to the immediate vicinity of the interface. The proposed single-domain, volume-average framework provides an efficient and mechanistic description of the reactive zone in porous media and a free layer. The resulting effective coefficients can be directly incorporated as efficient factors into process-scale models and optimization studies where reactive porous layers are coupled with adjacent multiphase flow regions.
| Country | México |
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| Student Awards | I would like to submit this presentation into the Earth Energy Science (EES) and Capillarity Student Poster Awards. |
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