https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 16 Mar 2026 02:04:58 GMT 2026-03-16T02:04:58Z http://hdl.handle.net/10985/9755 Towards a new method of porosimetry: principles and experiments RODRIGUEZ DE CASTRO, Antonio; AHMADI-SENICHAULT, Azita; BRUNEAU, Denis; OMARI, Aziz Current experimental methods used to determine pore size distributions (PSD) in porous media present several drawbacks such as toxicity of employed fluids (e.g. mercury porosimetry). Theoretical basis of a new method to obtain the PSD of porous media has been proposed in the literature [1, 2] ... Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/9755 2013-01-01T00:00:00Z RODRIGUEZ DE CASTRO, Antonio AHMADI-SENICHAULT, Azita BRUNEAU, Denis OMARI, Aziz Current experimental methods used to determine pore size distributions (PSD) in porous media present several drawbacks such as toxicity of employed fluids (e.g. mercury porosimetry). Theoretical basis of a new method to obtain the PSD of porous media has been proposed in the literature [1, 2] ... http://hdl.handle.net/10985/9928 Direct numerical simulation of colloid transport at the microscopic scale: influence of ionic strength in the presence of a rough surface SEFRIOUI, Nisrine; AHMADI-SENICHAULT, Azita; BERTIN, Henri; OMARI, Aziz The way colloids are transported, deposited or detached in porous media is of great importance in many practical problems such as filtration, environmental issues, petroleum engineering, … In this work, direct numerical simulations of the transport of a single particle near the fluid/solid interface have been performed. For this purpose, new routines have been implemented in a research code in order to take into account DLVO forces for smooth and rough pore surfaces. A dimensional analysis is performed, pointing out the important role of the ratio of electrostatic forces to the hydrodynamic forces on the particle behaviour. The test cases considered are chosen on the basis of experimental results presented in the literature. Transport of a particle near a solid surface is simulated for a given Reynolds number at different values of ionic strength and the influence of various surface roughness types are analysed. The simulations illustrate three different behaviours: (i) the particle is transported by the bulk fluid (ii) the particle is adsorbed and rolls on the solid surface (iii) the particle is adsorbed by the surface and is blocked. An analysis in terms of residence time is proposed. Simulations also show that an increase in the Reynolds number leads to the mobilisation of the particle in all cases studied. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/9928 2012-01-01T00:00:00Z SEFRIOUI, Nisrine AHMADI-SENICHAULT, Azita BERTIN, Henri OMARI, Aziz The way colloids are transported, deposited or detached in porous media is of great importance in many practical problems such as filtration, environmental issues, petroleum engineering, … In this work, direct numerical simulations of the transport of a single particle near the fluid/solid interface have been performed. For this purpose, new routines have been implemented in a research code in order to take into account DLVO forces for smooth and rough pore surfaces. A dimensional analysis is performed, pointing out the important role of the ratio of electrostatic forces to the hydrodynamic forces on the particle behaviour. The test cases considered are chosen on the basis of experimental results presented in the literature. Transport of a particle near a solid surface is simulated for a given Reynolds number at different values of ionic strength and the influence of various surface roughness types are analysed. The simulations illustrate three different behaviours: (i) the particle is transported by the bulk fluid (ii) the particle is adsorbed and rolls on the solid surface (iii) the particle is adsorbed by the surface and is blocked. An analysis in terms of residence time is proposed. Simulations also show that an increase in the Reynolds number leads to the mobilisation of the particle in all cases studied. http://hdl.handle.net/10985/9929 On the influence of ionic strength on colloid transport in porous media in the presence of a rough surface : numerical simulation at the microscopic scale SEFRIOUI, Nisrine; AHMADI-SENICHAULT, Azita; BERTIN, Henri; OMARI, Aziz The understanding of Colloids transport, deposit or detachment in porous media is of central importance in many practical problems such as filtration, environmental issues and petroleum engineering. In particular, the interaction of colloids with the grain surfaces is a complex problem involving combination of short range physico-chemical forces, acting at the “interface scale” with the hydrodynamics in the pore space. The understating of the processes at these small scales is crucial for the description of colloid transport processes under different physicochemical and hydrodynamic conditions at larger scales. General experimental features of colloid deposition and their detachment after a flooding with brine of ionic strength and pH different from the resident one have been reported in literature and successfully predicted using DLVO theory (Canseco et al., 2009). However and despite various efforts, such prediction remains only qualitative. It is usually believed that the observed discrepancies arise from grain or colloid heterogeneities. Such heterogeneities may concern electrostatic charge or surface topography or both.(Ducker et al., 1991; Elimelech & O’Melia, 1990). The objective of this work is to study the influence of grain surface roughness on the transport, deposit and detachment of a colloidal particle under various physicochemical and hydrodynamic conditions. For this purpose, direct numerical simulations of the transport of a single particle near the fluid/solid interface have been performed. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/9929 2012-01-01T00:00:00Z SEFRIOUI, Nisrine AHMADI-SENICHAULT, Azita BERTIN, Henri OMARI, Aziz The understanding of Colloids transport, deposit or detachment in porous media is of central importance in many practical problems such as filtration, environmental issues and petroleum engineering. In particular, the interaction of colloids with the grain surfaces is a complex problem involving combination of short range physico-chemical forces, acting at the “interface scale” with the hydrodynamics in the pore space. The understating of the processes at these small scales is crucial for the description of colloid transport processes under different physicochemical and hydrodynamic conditions at larger scales. General experimental features of colloid deposition and their detachment after a flooding with brine of ionic strength and pH different from the resident one have been reported in literature and successfully predicted using DLVO theory (Canseco et al., 2009). However and despite various efforts, such prediction remains only qualitative. It is usually believed that the observed discrepancies arise from grain or colloid heterogeneities. Such heterogeneities may concern electrostatic charge or surface topography or both.(Ducker et al., 1991; Elimelech & O’Melia, 1990). The objective of this work is to study the influence of grain surface roughness on the transport, deposit and detachment of a colloidal particle under various physicochemical and hydrodynamic conditions. For this purpose, direct numerical simulations of the transport of a single particle near the fluid/solid interface have been performed. http://hdl.handle.net/10985/9722 Towards a new method of porosimetry: principles and experiments RODRIGUEZ DE CASTRO, Antonio; OMARI, Aziz; AHMADI-SENICHAULT, Azita; BRUNEAU, Denis Abstract Current experimental methods used to determine pore size distributions (PSD) of porous media present several drawbacks such as toxicity of the employed fluids (e.g., mercury porosimetry). The theoretical basis of a new method to obtain the PSD by injecting yield stress fluids through porous media and measuring the flow rate Q at several pressure gradients ∇P was proposed in the literature. On the basis of these theoretical considerations, an intuitive approach to obtain PSD from Q(∇P) is presented in this work. It relies on considering the extra increment of Q when ∇P is increased, as a consequence of the pores of smaller radius newly incorporated to the flow. This procedure is first tested and validated on numerically generated experiments. Then, it is applied to exploit data coming from laboratory experiments and the obtained PSD showgood agreement with the PSD deduced frommercury porosimetry. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/9722 2013-01-01T00:00:00Z RODRIGUEZ DE CASTRO, Antonio OMARI, Aziz AHMADI-SENICHAULT, Azita BRUNEAU, Denis Abstract Current experimental methods used to determine pore size distributions (PSD) of porous media present several drawbacks such as toxicity of the employed fluids (e.g., mercury porosimetry). The theoretical basis of a new method to obtain the PSD by injecting yield stress fluids through porous media and measuring the flow rate Q at several pressure gradients ∇P was proposed in the literature. On the basis of these theoretical considerations, an intuitive approach to obtain PSD from Q(∇P) is presented in this work. It relies on considering the extra increment of Q when ∇P is increased, as a consequence of the pores of smaller radius newly incorporated to the flow. This procedure is first tested and validated on numerically generated experiments. Then, it is applied to exploit data coming from laboratory experiments and the obtained PSD showgood agreement with the PSD deduced frommercury porosimetry. http://hdl.handle.net/10985/9978 On the Determination of Pore size distribution from Injection of yield stress fluids through model porous media RODRIGUEZ DE CASTRO, Antonio; MALVAULT, Guillaume; AHMADI-SENICHAULT, Azita; AMBARI, Abdelhak; BRUNEAU, Denis; CHAMPMARTIN, Stephane; OMARI, Aziz Current methods used to determine pore size distribution of porous media (as mercury porosimetry) present several drawbacks the main of which is their toxicity An innovative method using yield stress fluids has been proposed in the literature. The main idea in these works is that using fluids with a threshold below which the fluid does not flow allows obtaining the pore size distribution by simply measuring the evolution of the flow rate versus pressure gradient. In fact this attractive method should be carefully handled and very precise experimental results are needed to make the method tractable in order to meet the targeted objective. This will be discussed through presentation of our recent experimental results. In these experiments two kinds of fluids where specifically formulated and rheologically characterized. These fluids were injected in both simple and complex artificial porous media and flow rate-pressure gradient relationships where established allowing us to estimate the pore size distribution. Sun, 01 Jan 2012 00:00:00 GMT http://hdl.handle.net/10985/9978 2012-01-01T00:00:00Z RODRIGUEZ DE CASTRO, Antonio MALVAULT, Guillaume AHMADI-SENICHAULT, Azita AMBARI, Abdelhak BRUNEAU, Denis CHAMPMARTIN, Stephane OMARI, Aziz Current methods used to determine pore size distribution of porous media (as mercury porosimetry) present several drawbacks the main of which is their toxicity An innovative method using yield stress fluids has been proposed in the literature. The main idea in these works is that using fluids with a threshold below which the fluid does not flow allows obtaining the pore size distribution by simply measuring the evolution of the flow rate versus pressure gradient. In fact this attractive method should be carefully handled and very precise experimental results are needed to make the method tractable in order to meet the targeted objective. This will be discussed through presentation of our recent experimental results. In these experiments two kinds of fluids where specifically formulated and rheologically characterized. These fluids were injected in both simple and complex artificial porous media and flow rate-pressure gradient relationships where established allowing us to estimate the pore size distribution. http://hdl.handle.net/10985/10902 Displacement of colloidal dispersions in Porous Media: experimental & numerical approaches AHMADI-SENICHAULT, Azita; CANSECO, Vladimir; SEFRIOUI-CHAIBAINOU, Nisrine; OMARI, Aziz; BERTIN, Henri The main objective of this paper is to give more insight on colloids deposition and re-entrainment in presence of a rough surface. Experiments on retention and release of colloids in a porous medium are first presented. The influence of physicochemical and hydrodynamic conditions is investigated. The experimental results cannot be qualitatively interpreted using the DLVO theory and knowledges at pore scale are then needed. A 3D numerical simulation approach at the pore scale is therefore proposed where the motion of colloids is solved in presence of collector surfaces bearing various kinds of asperities and by taking into account physico-chemical interactions calculated at each time step during colloid movement. It is obviously observed that both deposition and mobilization of particles are dependent on solution chemistry and hydrodynamic conditions and are significantly affected by the form and size of the local roughness of the pore surface. Therefore, depending on solution ionic strength and surface topography, colloids may be adsorbed or not and when a particle is retained an increase of flow strength is then needed to remove it and such an increase is specific to the location of occurrence of the adsorption step. In general, simulation results allow us to explain our experimental results that show that by steeply increasing the flow strength, more and more fractions of particles retained inside the porous medium are released until all particles are removed. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/10902 2016-01-01T00:00:00Z AHMADI-SENICHAULT, Azita CANSECO, Vladimir SEFRIOUI-CHAIBAINOU, Nisrine OMARI, Aziz BERTIN, Henri The main objective of this paper is to give more insight on colloids deposition and re-entrainment in presence of a rough surface. Experiments on retention and release of colloids in a porous medium are first presented. The influence of physicochemical and hydrodynamic conditions is investigated. The experimental results cannot be qualitatively interpreted using the DLVO theory and knowledges at pore scale are then needed. A 3D numerical simulation approach at the pore scale is therefore proposed where the motion of colloids is solved in presence of collector surfaces bearing various kinds of asperities and by taking into account physico-chemical interactions calculated at each time step during colloid movement. It is obviously observed that both deposition and mobilization of particles are dependent on solution chemistry and hydrodynamic conditions and are significantly affected by the form and size of the local roughness of the pore surface. Therefore, depending on solution ionic strength and surface topography, colloids may be adsorbed or not and when a particle is retained an increase of flow strength is then needed to remove it and such an increase is specific to the location of occurrence of the adsorption step. In general, simulation results allow us to explain our experimental results that show that by steeply increasing the flow strength, more and more fractions of particles retained inside the porous medium are released until all particles are removed. http://hdl.handle.net/10985/8835 Numerical simulation of retention and release of colloids in porous media at the pore scale SEFRIOUI, Nisrine; AHMADI-SENICHAULT, Azita; OMARI, Aziz; BERTIN, Henri Transport of a solid colloidal particle was simulated at the pore scale in presence of surface roughness and particle/pore physicochemical interaction by adopting a “one fluid” approach. A code developed in our laboratory was used to solve equations of motion, while implementing additional modules in order to take into account lubrication and physicochemical forces. Particles were recognized through a phase indicator function and the particle/fluid interface position at each instant was obtained by solving a transport equation. Roughnesses of different shapes were considered and the magnitude of the particle/pore physicochemical interaction was monitored through the change of the ionic strength of the suspending fluid. We first show that if pore surface is smooth no retention of the transported particle occurs whether the particle/pore surface is attractive or repulsive. However for shape roughnesses of “peak” or “valley”, particles may be retained inside pores or not depending on the considered ionic strength. In absence of particle retention, the residence time (the time needed for a particle to travel a characteristic pore distance) is finite and was found to be an increasing function of ionic strength for every considered roughness at fixed hydrodynamic conditions. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10985/8835 2013-01-01T00:00:00Z SEFRIOUI, Nisrine AHMADI-SENICHAULT, Azita OMARI, Aziz BERTIN, Henri Transport of a solid colloidal particle was simulated at the pore scale in presence of surface roughness and particle/pore physicochemical interaction by adopting a “one fluid” approach. A code developed in our laboratory was used to solve equations of motion, while implementing additional modules in order to take into account lubrication and physicochemical forces. Particles were recognized through a phase indicator function and the particle/fluid interface position at each instant was obtained by solving a transport equation. Roughnesses of different shapes were considered and the magnitude of the particle/pore physicochemical interaction was monitored through the change of the ionic strength of the suspending fluid. We first show that if pore surface is smooth no retention of the transported particle occurs whether the particle/pore surface is attractive or repulsive. However for shape roughnesses of “peak” or “valley”, particles may be retained inside pores or not depending on the considered ionic strength. In absence of particle retention, the residence time (the time needed for a particle to travel a characteristic pore distance) is finite and was found to be an increasing function of ionic strength for every considered roughness at fixed hydrodynamic conditions. http://hdl.handle.net/10985/9965 Macroscopic modeling of colloids adsorption in porous media SEFRIOUI, Nisrine; AHMADI-SENICHAULT, Azita; BERTIN, Henri; OMARI, Aziz Natural porous media such as soils or aquifers, contain colloidal particles. Depending on geochemical and hydrodynamic conditions, they can be transported by water, developing high reactivity and mobility. They may therefore act as vectors of pollutants and viruses dissemination in soils and groundwater. Some colloidal particles like bacteria are also likely to present a risk to the environment and health. However, adsorption of colloids on the solid matrix may severely limit their mobility in porous media, consequently, their fate depends on physico-chemical and hydrodynamic conditions. Previous experimental studies [1] highlighted the role of ionic strength and Peclet number on both adsorption and release of particles. The objective of this work is to propose a macroscopic model (Darcy scale) that accurately describes the transport of colloids in the presence of adsorption process observed experimentally. Sat, 01 Jan 2011 00:00:00 GMT http://hdl.handle.net/10985/9965 2011-01-01T00:00:00Z SEFRIOUI, Nisrine AHMADI-SENICHAULT, Azita BERTIN, Henri OMARI, Aziz Natural porous media such as soils or aquifers, contain colloidal particles. Depending on geochemical and hydrodynamic conditions, they can be transported by water, developing high reactivity and mobility. They may therefore act as vectors of pollutants and viruses dissemination in soils and groundwater. Some colloidal particles like bacteria are also likely to present a risk to the environment and health. However, adsorption of colloids on the solid matrix may severely limit their mobility in porous media, consequently, their fate depends on physico-chemical and hydrodynamic conditions. Previous experimental studies [1] highlighted the role of ionic strength and Peclet number on both adsorption and release of particles. The objective of this work is to propose a macroscopic model (Darcy scale) that accurately describes the transport of colloids in the presence of adsorption process observed experimentally. http://hdl.handle.net/10985/9751 Displacement of Colloidal Dispersions in Porous Media: Experimental & Numerical Approaches AHMADI-SENICHAULT, Azita; OMARI, Aziz; BERTIN, Henri The displacement of colloidal dispersions is of particular interest in many applications ranging from environmental issues to petroleum recovery. Natural porous media such as soils, aquifers or reservoirs contain colloidal particles of different nature (bacteria, viruses, clay, metal complexes …). Colloids can act as vehicles for micro organisms’ transport in aquifers causing danger for human health. In petroleum recovery techniques, water containing colloids is sometimes injected and their release and adsorption may alter the petrophysical properties of reservoirs causing their damage. This talk focuses on the study of colloid transport in porous media under different hydrodynamic and physicochemical conditions (pH, salinity) using both experimental and numerical approaches. Typical laboratory experiments consist in the injection of a colloidal dispersion of a given concentration in a porous column. The analysis of the effluents after brine-flushing allows investigating the kinetics of release and adsorption of colloids inside the porous medium. In-situ investigations are performed either by post-mortem destructive methods or by using more sophisticated non-destructive methods. Moreover, a first approach to model these processes consists in solving the appropriate convection-dispersion-reaction equations involving macroscopic properties. Although this gives valuable qualitative insight on the displacement mechanisms, a more detailed study at the pore-scale is needed. Numerical approaches have been used at the pore-scale to study the displacement of colloidal particles. As a first approximation, the transport of the mass center of the particles has been considered. More complete numerical methods have allowed to study the transport of a colloidal particle taking into account pore-surface roughness, hydrodynamic forces and particle/pore physicochemical interactions (DLVO forces monitored through the change of the ionic strength of the suspending fluid). An overview of our experimental and numerical studies will be presented. Thu, 01 Jan 2015 00:00:00 GMT http://hdl.handle.net/10985/9751 2015-01-01T00:00:00Z AHMADI-SENICHAULT, Azita OMARI, Aziz BERTIN, Henri The displacement of colloidal dispersions is of particular interest in many applications ranging from environmental issues to petroleum recovery. Natural porous media such as soils, aquifers or reservoirs contain colloidal particles of different nature (bacteria, viruses, clay, metal complexes …). Colloids can act as vehicles for micro organisms’ transport in aquifers causing danger for human health. In petroleum recovery techniques, water containing colloids is sometimes injected and their release and adsorption may alter the petrophysical properties of reservoirs causing their damage. This talk focuses on the study of colloid transport in porous media under different hydrodynamic and physicochemical conditions (pH, salinity) using both experimental and numerical approaches. Typical laboratory experiments consist in the injection of a colloidal dispersion of a given concentration in a porous column. The analysis of the effluents after brine-flushing allows investigating the kinetics of release and adsorption of colloids inside the porous medium. In-situ investigations are performed either by post-mortem destructive methods or by using more sophisticated non-destructive methods. Moreover, a first approach to model these processes consists in solving the appropriate convection-dispersion-reaction equations involving macroscopic properties. Although this gives valuable qualitative insight on the displacement mechanisms, a more detailed study at the pore-scale is needed. Numerical approaches have been used at the pore-scale to study the displacement of colloidal particles. As a first approximation, the transport of the mass center of the particles has been considered. More complete numerical methods have allowed to study the transport of a colloidal particle taking into account pore-surface roughness, hydrodynamic forces and particle/pore physicochemical interactions (DLVO forces monitored through the change of the ionic strength of the suspending fluid). An overview of our experimental and numerical studies will be presented. http://hdl.handle.net/10985/22945 A thermal resistant and flame retardant separator reinforced by attapulgite for lithium-ion batteries via multilayer coextrusion LI, Yajie; YANG, Haicun; AHMADI-SENICHAULT, Azita; OMARI, Aziz; PU, Hongting Multilayer separators are widely used due to their wide shutdown window by combining lower melting tem- perature and higher melting temperature of different layers. With the development of high power lithium-ion batteries, multilayer separators equipped with effective thermal stability and flame retardancy are highly required. Herein, the poly(methyl methacrylate) modified attapulgite (ATPM) is selected as the heat resistant reinforcing component and blended with polypropylene (PP)/polyethylene (PE) respectively. Then we prepare PP(ATPM)/PE(ATPM) separators via multilayer coextrusion efficiently without multiple stretching processes, which can avoid serious separator shrinkage at elevated temperature. The intertwined ATPM could not only enhance the separator integrity, but also produce water vapor and oxide anti-flaming isolation layers at high temperatures. The as-prepared separators, referred to as MC-TIPS PP/PE/ATPM, exhibit higher thermal stability (with negligible dimensional shrinkage up to 180 ◦C), better flame retardancy and wider shutdown temperature window (124–183 ◦C) than the commercial multilayer separators. Moreover, the introduction of ester and hydroxyl groups could improve the wettability and electrolyte uptake of the separators. These properties, as well as the potential for large-scale production of multilayer coextrusion, make MC-TIPS PP/PE/ATPM an ideal choice for high-power battery separators. Wed, 01 Jun 2022 00:00:00 GMT http://hdl.handle.net/10985/22945 2022-06-01T00:00:00Z LI, Yajie YANG, Haicun AHMADI-SENICHAULT, Azita OMARI, Aziz PU, Hongting Multilayer separators are widely used due to their wide shutdown window by combining lower melting tem- perature and higher melting temperature of different layers. With the development of high power lithium-ion batteries, multilayer separators equipped with effective thermal stability and flame retardancy are highly required. Herein, the poly(methyl methacrylate) modified attapulgite (ATPM) is selected as the heat resistant reinforcing component and blended with polypropylene (PP)/polyethylene (PE) respectively. Then we prepare PP(ATPM)/PE(ATPM) separators via multilayer coextrusion efficiently without multiple stretching processes, which can avoid serious separator shrinkage at elevated temperature. The intertwined ATPM could not only enhance the separator integrity, but also produce water vapor and oxide anti-flaming isolation layers at high temperatures. The as-prepared separators, referred to as MC-TIPS PP/PE/ATPM, exhibit higher thermal stability (with negligible dimensional shrinkage up to 180 ◦C), better flame retardancy and wider shutdown temperature window (124–183 ◦C) than the commercial multilayer separators. Moreover, the introduction of ester and hydroxyl groups could improve the wettability and electrolyte uptake of the separators. These properties, as well as the potential for large-scale production of multilayer coextrusion, make MC-TIPS PP/PE/ATPM an ideal choice for high-power battery separators.