M³: a multiphase, multiconstituant and multiprocess code to model contaminated

70% of the contaminated sites in France are with organic compounds (hydrocarbons, chlorinated solvents,…). Modeling such contamination can be difficult as it is governed by numerous and highly coupled mechanisms (multiphase flow, dissolution and volatilization of Non Aqueous Phase Liquids(NAPL), sorption and biodegradation). Whereas many numerical codes include some of these mechanisms, none of them, to our knowledge, allows the modeling of the full set of mechanisms. A new code, called M3 for Multiphase, Multicomponent, Multiprocess, is then being developed to address this kind of modeling. The originality of the code stands both in the diversity of the mechanisms and in original formalisms such as non-local equilibrium dissolution of NAPL or biodegradation formalism dedicated to chlorinated solvents. After a short description of the numerical code, test cases will be presented to highlight the capacity of the code to model many situations that might be accoutered when dealing with contaminated sites (prediction of an accidental spill, temporal evolution of a source zone and its impact on aquifers, assessment of biodegradation…)

CubicM, un code de calcul pour simuler le devenir de polluants organiques dans le milieu souterrain

Le logiciel CubicM est dédié à la modélisation du devenir des polluants organiques dans le milieu souterrain. L'originalité du code tien dans le fait que i)il intègre l'ensemble des mécanismes qui régissent le comportement de ce type de polluants (écoulements triphasiques / transport / dissolution / biodégradation ...); ii) des formalismes mathématiques originaux ont été inclus afin de gagner en précision. Cet outil permet ainsi de modéliser un grand nombre de situations rencontrées sur des sites pollués

Multiphase multicomponent modelling of the NAPL transfer in the subsurface using Method of Lines

This paper presents the three dimensional multicomponent multi-phase simulator CUBICM (M3 ) combining reactive transport and mass transfer modules. The main purpose of this tool is to evaluate and quantify Non-Aqueous Phase Liquid (NAPL) plume attenuation by soil microorganisms and kinetic mass transfer processes such as dissolution, volatilization, sorption. Physical, biological and numerical concepts are given here in a fully embedded method of lines scheme using control volume finite element. The aim of the developed numerical code is to allow a flexible selection of physical formalisms via a dedicated Graphical User Interface in order to study the fate of pollutants in time and space. Various test cases are then illustrated with 2D and 3D semi-realistic heterogeneous configurations

Estimating the activation energy of bond hydrolysis by time-resolved weighing of dissolving crystals

International audienceAbstract Bond-breaking activation energy E B is nowadays a key parameter for understanding and modeling crystal dissolution processes. However, a methodology to estimate E B based on classical dissolution experiments still does not exist. We developed a new method based on the calibration of a Kossel type dissolution model on measured dissolution rates obtained by mass (or volume) variations over time. The dissolution model does not depend on the geometry of the crystal surface but only on the density of the different types of sites (kink, step, terrace, bulk). The calibration method was applied to different experimental setups (flow through and batch) with different ways of estimating the dissolution rates (solute concentration in the fluid, surface topography) for calcite crystals. Despite the variety of experimental conditions, the estimated bond-breaking activation energies were very close to each other (between 31 and 35 kJ/mol) and in good agreement with ab initio calculations

On the prediction of three-phase relative permeabilities using two-phase constitutive relationships

The predictions of two recent and two classical mathematical models are compared with experimentally measured three-phase relative permeabilities. Experimentally determined constitutive relationships in two-phase systems were used as model input parameters to numerically predict relative permeabilities (k r ) in three-phase systems. Then the estimated results were compared with experimental three-phase permeabilities measured along decreas- ing water saturation/decreasing oil saturation/increasing gas saturation (DDI) paths. The results of the individual models to each of the three fluids involved (water, oil, and gas) were analyzed in detail. The simulated results showed that the Total Differential (TD) compatible model overestimates significantly both the global mobilities as well as the relative phase permeabilities in the three-phase system. There was improvement in the prediction with the TD compatible model when experimental data were used to locally impose the global mobility and fractional water and gas fluxes in the ternary diagram. Globally, the best prediction of the measured k r values was obtained with the so-called mechanistic model. However, its numerical implementation requires a prelimi- nary calibration of the relative phase permeabilities in a three-phase system against experimental data along one DDI path to quantify the required six characteristic coefficients. In contrast to the TD compatible model, which by construction does not exhibit any numerical instabilities, elliptic zones in the water-oil (NAPL)-gas ternary diagram were identified in the mechanistic model

M³ : a multiphase, multiconstituant and multiprocess code to model contaminated

International audience70% of the contaminated sites in France are with organic compounds (hydrocarbons, chlorinated solvents,…). Modeling such contamination can be difficult as it is governed by numerous and highly coupled mechanisms (multiphase flow, dissolution and volatilization of Non Aqueous Phase Liquids(NAPL), sorption and biodegradation). Whereas many numerical codes include some of these mechanisms, none of them, to our knowledge, allows the modeling of the full set of mechanisms. A new code, called M3 for Multiphase, Multicomponent, Multiprocess, is then being developed to address this kind of modeling. The originality of the code stands both in the diversity of the mechanisms and in original formalisms such as non-local equilibrium dissolution of NAPL or biodegradation formalism dedicated to chlorinated solvents. After a short description of the numerical code, test cases will be presented to highlight the capacity of the code to model many situations that might be accoutered when dealing with contaminated sites (prediction of an accidental spill, temporal evolution of a source zone and its impact on aquifers, assessment of biodegradation…)

M³ : a multiphase, multiconstituant and multiprocess code to model contaminated

International audience70% of the contaminated sites in France are with organic compounds (hydrocarbons, chlorinated solvents,…). Modeling such contamination can be difficult as it is governed by numerous and highly coupled mechanisms (multiphase flow, dissolution and volatilization of Non Aqueous Phase Liquids(NAPL), sorption and biodegradation). Whereas many numerical codes include some of these mechanisms, none of them, to our knowledge, allows the modeling of the full set of mechanisms. A new code, called M3 for Multiphase, Multicomponent, Multiprocess, is then being developed to address this kind of modeling. The originality of the code stands both in the diversity of the mechanisms and in original formalisms such as non-local equilibrium dissolution of NAPL or biodegradation formalism dedicated to chlorinated solvents. After a short description of the numerical code, test cases will be presented to highlight the capacity of the code to model many situations that might be accoutered when dealing with contaminated sites (prediction of an accidental spill, temporal evolution of a source zone and its impact on aquifers, assessment of biodegradation…)

CubicM, un code de calcul pour simuler le devenir de polluants organiques dans le milieu souterrain

National audienceLe logiciel CubicM est dédié à la modélisation du devenir des polluants organiques dans le milieu souterrain. L'originalité du code tien dans le fait que i)il intègre l'ensemble des mécanismes qui régissent le comportement de ce type de polluants (écoulements triphasiques / transport / dissolution / biodégradation ...); ii) des formalismes mathématiques originaux ont été inclus afin de gagner en précision. Cet outil permet ainsi de modéliser un grand nombre de situations rencontrées sur des sites pollués