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85 results on '"Castellani, Romain"'

1. Aggregation and disaggregation processes in clusters of particles: simple numerical and theoretical insights of the competition in 2D geometries

Author

Bouthier, Louis-Vincent, Castellani, Romain, Manneville, Sébastien, Poulesquen, Arnaud, Valette, Rudy, and Hachem, Elie

Subjects
Condensed Matter - Soft Condensed Matter, Physics - Fluid Dynamics
Abstract

Aggregation and disaggregation of clusters of attractive particles under flow are studied from numerical and theoretical points of view. Two-dimensional molecular dynamics simulations of both Couette and Poiseuille flows highlight the growth of the average steady-state cluster size as a power law of the adhesion number, a dimensionless number that quantifies the ratio of attractive forces to shear stress. Such a power-law scaling results from the competition between aggregation and disaggregation processes, as already reported in the literature. Here, we rationalize this behavior through a model based on an energy function, which minimization yields the power-law exponent in terms of the cluster fractal dimension, in good agreement with the present simulations and with previous works., Comment: 13 pages, 6 figures

Published
2022

2. Proposition of extension of models relating rheological quantities and microscopic structure through the use of a double fractal structure

Author

Bouthier, Louis-Vincent, Castellani, Romain, Hachem, Elie, and Valette, Rudy

Subjects
Condensed Matter - Soft Condensed Matter, Physics - Fluid Dynamics
Abstract

Colloidal suspensions and the relation between their rheology and their microstructure is investigated. The literature showed great evidence of the relation between rheological quantities and particle volume fraction, ignoring the influence of the cluster. We propose to extend previous models using a new double fractal structure which allows, first, to recover the well-known models on the case of percolated system and, second, to capture the influence of the cluster size. This new model emphasises the necessity of such structure to account for recent experimental results. Then, the model is compared with data coming from the literature and shows close agreement., Comment: 5 pages, 3 figures, 1 table, letter

Published
2022
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4. The MMX rover: performing in situ surface investigations on Phobos

Author

Michel, Patrick, Ulamec, Stephan, Böttger, Ute, Grott, Matthias, Murdoch, Naomi, Vernazza, Pierre, Sunday, Cecily, Zhang, Yun, Valette, Rudy, Castellani, Romain, Biele, Jens, Tardivel, Simon, Groussin, Olivier, Jorda, Laurent, Knollenberg, Jörg, Grundmann, Jan Thimo, Arrat, Denis, Pont, Gabriel, Mary, Stephane, Grebenstein, Markus, Miyamoto, Hirdy, Nakamura, Tomoki, Wada, Koji, Yoshikawa, Kent, and Kuramoto, Kiyoshi

Published
2022
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5. Theoretical and experimental study of the flow of a molten polymer in a micro-compounder

Author

Berton, Irene, Castellani, Romain, Sardo, Lucas, Valette, Rudy, and Vergnes, Bruno

Subjects
Plastics -- Extrusion, Engineering and manufacturing industries, Science and technology
Abstract

Micro-compounders are more and more used to characterize and optimize the formulations and the flow conditions of complex materials, with very low quantities, around a few grams. These machines are composed of a small-size conical twinscrew extruder, coupled with a recirculating channel, in which the material can be processed during a fixed time and a certain number of cycles, before being purged. However, the precise flow conditions inside these machines are not well known, what makes an optimal interpretation of the results difficult. Therefore, in this paper, a theoretical model based on continuum mechanics is proposed to calculate the flow in the recirculating mode. An experimental study on a wellchosen polymer is carried out to define the influences of the main processing parameters (screw speed, mass of material, barrel temperature) and to validate the model. Despite the simplicity of the theoretical approach, the calculated results are in satisfactory agreement with the experiments. KEYWORDS flow modeling, micro-compounder, molten polymer, twin-screw extrusion, 1 | INTRODUCTION Mixing and compounding of polymers are an essential part of the polymer industry. At an industrial level, these operations are generally carried out using twin-screw extruders, able [...]

Published
2021
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8. The role of viscoplastic drop shape in impact

Author

Isukwem, Kindness, primary, Godefroid, Julie, additional, Monteux, Cécile, additional, Bouttes, David, additional, Castellani, Romain, additional, Hachem, Elie, additional, Valette, Rudy, additional, and Pereira, Anselmo, additional

Published
2023
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14. Rheology of plastisol formulations for coating applications

Author

Abdesselam, Yamina, Agassant, Jean-Franqois, Castellani, Romain, Valette, Rudy, Demay, Yves, Gourdin, Diego, and Peres, Richard

Subjects
Polymer rheology -- Observations, Polyvinyl chloride -- Mechanical properties, Suspensions (Chemistry) -- Mechanical properties, Engineering and manufacturing industries, Science and technology
Abstract

A plastisol is a suspension of PVC particles and mineral fillers in a liquid phase composed of plasticizer and adjuvants. Plastisol formulations are commonly used in coating processes for flooring application. In the knife-over-roll process, they are subjected to a wide range of shear rates (0-[10.sup.5] [s.sup.-1]). They are adjusted in order to fulfil the target end-use properties but their processability depends on their rheology. Plastisol based on three PVC resins with or without mineral filler have been investigated using a Couette device and a capillary rheometer. Results show a high impact of PVC particle content, particle sizes and distribution on rheology: a polydisperse formulation displays a shear-thinning behavior in the whole shear rates range and exhibits yield stress; a monodisperse formulation shows a shear thinning behavior at low shear rate, followed by a Newtonian plateau, then a more or less pronounced dilatancy peak depending on plasticizer rate and finally another shear-thinning behavior; a bidisperse resin stands in between. Filler content also impacts the rheology: shear thickening effects at intermediate shear rates decrease or even disappear; however, the viscosity increase is important for low shear rates and depends on the filler particle size and particle size distribution., INTRODUCTION A plastisol is a suspension of PVC particles in a liquid continuous phase composed of plasticizer, adjuvants such as stabilizers, pigments, blowing agents, and sometimes, mineral fillers. Plastisol formulations [...]

Published
2017
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20. Conception d'une cellule Couette excentrique transparente co- et contra-rotative pour étudier le comportement aux interfaces de fluides visqueux dans un cisaillement à surfaces libres

Author

Thirunavukkarasu, Prashanth, Castellani, Romain, Cohen, Celine, Fournier, Francis, Peuvrel-Disdier, Edith, Pignolet, Arnaud, Valette, Rudy, Vergnes, Bruno, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Manuf Franc Pneumatic Michelin (M.F.P. Michelin), Société Michelin, Institut de Physique de Nice (INPHYNI), Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), and OSUM project, FUI AAP23, funded by BPiFrance.

Subjects
Physics::Fluid Dynamics, Viscous flow, Couette cell, Contact line motion, Free surface shear, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [SPI.MAT]Engineering Sciences [physics]/Materials, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract

In the present work, a prototype was developed to observe the flow behavior of viscous fluids (10^3 to 10^5 Pa.s) under free surface shear. The geometry of the prototype is an eccentric Couette cell where both cylinders can rotate in the same or opposite directions. Transparent windows permit in-situ observations during flow. The design, development and testing of the prototype with a viscous model fluid are reported in this paper. In order to obtain information on contact lines and free surfaces under shear, the flow behaviour of a small fluid volume was investigated in co-and counter-rotating conditions. The different flow conditions and information that can be obtained are described. A particular attention is paid to determine steady state flow conditions.

Published
2021

21. The MMX Rover: Performing in-situ Surface Investigations on Phobos

Author

Michel, Patrick, primary, Ulamec, Stephan, additional, Boettger, Ute, additional, Grott, Matthias, additional, Murdoch, Naomi, additional, Vernazza, Pierre, additional, Sunday, Cecily, additional, Zhang, Yun, additional, Valette, Rudy, additional, Castellani, Romain, additional, Biele, Jens, additional, Tardivel, Simon, additional, Groussin, Olivier, additional, Jorda, Laurent, additional, Knollenberg, Joerg, additional, Grundmann, Jan Thimo, additional, Arrat, Denis, additional, Pont, Gabriel, additional, Mary, Stéphane, additional, Grebenstein, Markus, additional, Miyamoto, Hirdy, additional, Nakamura, Tomoki, additional, Wada, Koji, additional, Yoshikawa, Kent, additional, and Kuramoto, Kiyoshi, additional

Published
2021
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22. Etude de la rhéologie de pâtes céramiques pour la mise en forme de combustible nucléaire par extrusion

Author

Mougard Camacho, Pierre-François, Poulesquen, Arnaud, Doreau, Franck, Castellani, Romain, Valette, Rudy, Castellani, Romain, DEN/DMRC/SFMA/LFC (LFC), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’étude des Ciments et Bitumes pour le Conditionnement (LCBC), Département de recherche sur les technologies pour l'enrichissement, le démantèlement et les déchets (DE2D), Mines Paris - PSL (École nationale supérieure des mines de Paris), and Département de recherche sur les Procédés et Matériaux pour les Environnements complexes (DPME)

Subjects
[PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [SPI.MAT] Engineering Sciences [physics]/Materials, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials, [PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience

Published
2018

23. Etudes rheologiques de pates ceramique pour la mise en forme de combustible nucleaire par extrusion

Author

Mougard Camacho, P.-F., Poulesquen, A., Doreau, F., Castellani, Romain, Valette, Rudy, CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL), and MINES ParisTech - École nationale supérieure des mines de Paris

Subjects
[PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Extrusion, Squeeze Test, Rheologie, Ceramique, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]
Abstract

International audience; Nuclear MOx -(U,Pu)O2- fuels, are shaped into pellets by dry-pressing a mixture of UO2/PuO2 . This process relies on several steps, among which the materials are powdered (crushing, mixing, sieving, pressing). It presents proven benefits, such as ease of implementation and high production rates. Alternative shaping processes based on materials in a wet or liquid state, are interesting alternatives for the mixing steps. Indeed, they reduce the dust accumulation due to dry-powder processes. Moreover, such processes should enable a better control over the fired fuel microstructures, through a more homogeneous mixing in the first steps. Extrusion processes could prove useful to engineer fuel rods. This work is focused on understanding the rheology of ceramic pastes, to be able to control its extrusion.Yttrium oxide and titanium dioxide, acting as plutonium dioxide and uranium dioxide, were selected for their respective proximity regarding morphology, granulometry and electric neutral point. Criteria believed to be the main parameters physically dictating the agglomeration and flow of the ceramic pastes. The pastes were obtained with a 30cm3 roller blade mixer (Brabender). Organic additives were added to enable the extrusion of non-model, highly charged systems. A capillary rheometer (RH2000, Malvern Panalytical) and less-conventional squeeze test flows were used to study the rheology of such pastes. A ram-extruder was built and mounted on an electromechanical testing machine (Instron). Ceramic pastes, shaped into 20cm rods, without surface defect and withstanding the specifications for nuclear fuels (fired density, mechanical strength, roughness, dimensions, purity and composition and microstructure) were further characterized. Six parameters fitted Benbow-Bridgwater’s equation to predict the extrusion pressure when changing geometry and speed. Constitutive modelling has been carried out on the forces obtained from squeezing test set-ups. The compressive forces were found to be dependent on sample deformation, compressive speed and volume fraction of ceramics. Friction seems to play an important role in flows of the system studied. Traditional capillary experiments have also been found to be poorly reliable to successfully characterize the rheological behaviour of these complex systems.Extruding highly charged ceramics rods, respecting nuclear specifications, is challenging. Modelling such flows requires reliable rheological flow-configurations. Squeezing tests and modified models successfully predict these pastes behaviour under controlled flow conditions. Further work will focus on applying these revisited models on extrusion flows. The final goal will be to transpose the study on ceramic pastes with nuclear oxides.

Published
2019

24. Influence of the polarity of the matrix on the breakage mechanisms of lignocellulosic fibers during twin-screw extrusion

Author

Amornsakchai, Taweechai, Lemaitre, Alain, Berzin, Françoise, Lemkhanter, Loubna, Marcuello, Carlos, Chabbert, Brigitte, Aguié-Beghin, Véronique, Molinari, Michaël, Castellani, Romain, Vergnes, Bruno, Mahidol University [Bangkok], Fractionnement des AgroRessources et Environnement - UMR-A 614 (FARE), Université de Reims Champagne-Ardenne (URCA)-Institut National de la Recherche Agronomique (INRA)-SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS), Université de Reims Champagne-Ardenne (URCA), Centre de Mise en Forme des Matériaux (CEMEF), Centre National de la Recherche Scientifique (CNRS)-PSL Research University (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris, Fractionnement des AgroRessources et Environnement (FARE), Université de Reims Champagne-Ardenne (URCA)-Institut National de la Recherche Agronomique (INRA), Chimie et Biologie des Membranes et des Nanoobjets (CBMN), École Nationale d'Ingénieurs des Travaux Agricoles - Bordeaux (ENITAB)-Institut de Chimie du CNRS (INC)-Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Grand Est' Region and the EuropeanFEDER Program within the frame of COFILI, Grant/Award Number:D2015050245Grand Est' Region and the'Ardennes' department (France)theWallonie (Belgium)European FEDERProgramINTERREG project COMPOSENS

Subjects
Materials science, Polymers and Plastics, Plastics extrusion, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, chemistry.chemical_compound, Breakage, Materials Chemistry, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], Cellulose, Composite material, twin-screw extrusion, SISAL, ComputingMilieux_MISCELLANEOUS, computer.programming_language, Polypropylene, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], breakage, General Chemistry, interactions, 021001 nanoscience & nanotechnology, Nanocrystalline material, 0104 chemical sciences, chemistry, lignocellulosic fibers, Compounding, Ceramics and Composites, Extrusion, rheology, 0210 nano-technology, computer, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; In a series of previous papers, models describing the breakage of lignocellulosefibers during melt mixing process were established and applied to predict fibersize changes when compounding composites in a twin-screw extruder. Differ-ent types of fibers were studied (flax, hemp, sisal, etc), but always with thesame matrix, namely polypropylene (PP) compatibilized with PP grafted withmaleic anhydride (PP-g-MA). In the present study, the influence of the matrixwas characterized, by comparing the results obtained with nonpolar PP andpolar poly(butylene succinate) (PBS) of similar viscosity. For flax and hempfibers, morphology changes (in length and diameter) were characterized alongthe screws under various processing conditions (screw speed and feed rate).Whatever the conditions, breakage was more important with the PBS matrix.Moreover, the rheological properties of the composites were also different,indicating specific interactions between fibers and matrices. Atomic forcemicroscopy was used to measure the adhesion between the different matricesand AFM levers functionalized with nanocrystalline cellulose. The results con-firmed a better interaction between the nanocrystalline cellulose and the PBSmatrix compared to the PP one

Published
2019

25. Yield stress water-entry

Author

Soeiro Pereira, Anselmo, Sardo, Lucas, Castellani, Romain, Hachem, Elie, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2018

26. Pénétration dans un milieu granulaire sous très faible gravité : cas de la sonde Mascot sur l'astéroïde Ryugu

Author

Sardo, Lucas, Thuillet, Florian, Zhu, Zeqi, Gorce, Lauriane, Bhoonah, Rachna, Cerardi, Nicolas, Sangar, Joë, Castellani, Romain, Michel, Patrick, Hachem, Elie, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract

International audience

Published
2018

27. Composites thermoplastiques à fibres lignocellulosiques préparés par extrusion bivis

Author

Lemkhanter, Loubna, Berzin, Françoise, Chabbert, Brigitte, Kurek, Bernard, Castellani, Romain, Vergnes, Bruno, Fractionnement des AgroRessources et Environnement (FARE), Université de Reims Champagne-Ardenne (URCA)-Institut National de la Recherche Agronomique (INRA), Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Fractionnement des AgroRessources et Environnement - UMR-A 614 (FARE), Université de Reims Champagne-Ardenne (URCA)-Institut National de la Recherche Agronomique (INRA)-SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-PSL Research University (PSL)-MINES ParisTech - École nationale supérieure des mines de Paris

Subjects
[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2018

28. Abnormal Behaviors in the Capillary Rheometry of Plastisol Formulations

Author

Demay, Yves, Abdesselam, Yamina, Castellani, Romain, Agassant, Jean-François, Laboratoire Jean Alexandre Dieudonné (JAD), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS), Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Tarkett GDL

Subjects
[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2018

31. Enroulement d'un jet de fluide en loi puissance : simulation et observation de la structuration à l'impact

Author

Soeiro Pereira, Anselmo, Antoniotti, Alexandre, Castellani, Romain, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2017

32. Comportement rhéologique des plastisols en rhéométrie capillaire

Author

Demay, Yves, Abdesselam, Yamina, Castellani, Romain, Agassant, Jean-François, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2017

33. Prédictions quantitatives d'effondrement de barrages 2D et 3D par le modèle μ(I) : régimes quasi-statique, inertiel et lois d'échelles

Author

Riber, Stéphanie, Castellani, Romain, Hachem, Elie, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2017

34. Numerical simulation of granular collapses using µ(I) rheology

Author

Riber, Stéphanie, Castellani, Romain, Hachem, Elie, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience

Published
2017

35. Analyse numérique des instabilités de flambage dans un fluide rhéoépaississant

Author

Pereira, Anselmo, Castellani, Romain, Antoniotti, Alexandre, VALETTE, Rudy, Association Française de Mécanique, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Association Française de Mécanique (AFM)

Subjects
[PHYS]Physics [physics], jets, modèles rhéologiques, rhéoépaississement, loi de puissance, [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], fluides non-newtoniens, [PHYS.MECA]Physics [physics]/Mechanics [physics], [SPI.MECA.SOLID]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Solid mechanics [physics.class-ph], newtoniens, [SPI.MAT]Engineering Sciences [physics]/Materials, suspensions denses, analyse expérimentale/numérique, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], fluides non
Abstract

Colloque avec actes et comité de lecture. Internationale.; International audience; Une des phénomènes les plus élégants et néanmoins simples de la mécanique des fluides se produit lorsqu'un fluide visqueux tombe sur un plan, et vient ensuite s'enrouler de façon à former une spirale. Rencontrés aussi bien dans la vie de tous les jours (miel sur une biscotte) que dans des cas industriels plus pointus, ces instabilités de flambage cachent une physique riche et complexe malgré l'apparente simplicité des expériences qui les mettent en lumière. La complexité s'accroit encore davantage lorsque le matériau qui s'écoule est non-newtonien, par exemple dans le cas de suspensions, fréquemment rencontrées dans différents procédés (remplissage de récipients alimentaires, dépôts de couches...). La chute d'un jet et son enroulement impliquant des surfaces libres et une structuration du liquide après impact, il existe alors une forte demande pour décrire et prédire ces phénomènes, difficile à modéliser. C'est le sujet du présent travail dans lequel sont analysés numériquement des instabilités de flambage dans un fluide non-newtonien dont la viscosité varie selon une loi de puissance, afin de mettre en évidence des effets de rhéoépaississement sur ces instabilités. Quelques résultats numériques sont ensuite confrontés à des résultats expérimentaux en régime newtonien dont les paramètres ont été observés et mesurés à l'aide d'une caméra rapide.

Published
2017

36. Quantitative predictions of the µ(I) rheology in 2D and 3D granular column collapse: scaling laws and quasi-static vs. inertial regimes

Author

Valette, Rudy, Riber, Stéphanie, Castellani, Romain, Hachem, Elie, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), and Association Française de Mécanique (AFM)

Subjects
mu(I) rhéologie, calcul, effondrement, milieux granulaires, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

International audience; We introduce an accurate numerical method for the computation of 2D and 3D granular collapse under gravity flows using the μ(I) rheology. We show that this rheology can capture the two experimentally observed types of spreading and the corresponding scaling laws, and we provide an accurate sensitivity analysis to rheological constants. Finally, we underline the role of an additional length scale on the spreading dynamics.; Ce travail concerne la résolution numérique du problème d’effondrement 2D et 3D de colonne granulaire à l’aide du modèle μ(I). Nous montrons que ce modèle est capable de reproduire les deux régimes d’étalement observés expérimentalement, et nous présentons une étude de sensibilité aux paramètres du modèle. Finalement, nous mettons en évidence le rôle d’une échelle de longueur supplémentaire sur l’étalement, confirmé par analyse dimensionnelle.

Published
2017

37. Quantitative predictions of the mu(I) rheology in 2D and 3D granular column collapse: scaling laws and quasi-static vs. inertial regimes

Author

VALETTE, Rudy, Riber, Stéphanie, Castellani, Romain, Hachem, Elie, Association Française de Mécanique, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
constitutive models, granular collapse, [PHYS.MECA]Physics [physics]/Mechanics [physics], Rheology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract

Colloque avec actes et comité de lecture. Internationale.; International audience; Granular column collapse under gravity is a benchmark problem for several applications from geophysics to industry. It has been shown experimentally, for granular columns of initial aspect ratio a=h_i/r_i (height/width or radius), that for large enough values of a, the final width or radius r_?, reached after spreading, obeys the scaling law (r_?- r_i) / r_i ? a^2/3 in 2D and a^1/2 in 3D flows. It was also shown that the normalized distance-time data (t, x) plot exhibits a universal shape, independently of the grain type. Recently, Jop et al. proposed a pressure dependent viscoplastic continuum model called mu(I), where the extra-stress is defined using an effective friction coefficient that varies from low (quasi-static regime) to high values (inertial regime) when the inertial number I=|?|d(?/p)^1/2 (where ?=strain rate tensor, d=grain diameter, ?=grain density and p=pressure) reaches the (material dependent) parameter I0. In this paper, we study the pertinence mu(I) to predict 2D and 3D granular column collapse flows. A time-dependent regularization algorithm is proposed to solve this model, combined with anisotropic mesh adaptation to capture accurately the quasi-static vs. inertial flow zones, and using a variational multiscale method. A Level-Set method aims to capture and follow efficiently the interface between the fluid/air domain. We show that (i) the mu(I) model exhibit non unique solutions at early times (acceleration phase): mesh dependent short lengthscale instabilities (shear bands) appear, (ii) these instabilities do not subsist during the steady front velocity and deceleration phases, (iii) the universal distance-time plot shape is retrieved. Moreover, 2D and 3D results show that most of the flow is in a quasi-static regime, the inertial regime being only reached in a small volume at the front flow. 2D and 3D initial aspect ratio scaling laws for spreading distance are then accurately predicted. An accurate sensitivity analysis to rheological parameters is finally performed.

Published
2017

38. Quantitative predictions of 2D and 3D dam-break cases using mu(I) rheology

Author

Riber, Stéphanie, Castellani, Romain, Hachem, Elie, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract

International audience

Published
2017

39. Rise and coalescence of bubbles in a low Reynolds number flow: observations and simulation

Author

Castellani, Romain, Khalloufi, Mehdi, Marchal, Antoine, Poulesquen, Arnaud, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etudes de l'Enrobage des Déchets (L2ED), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Mines Paris - PSL (École nationale supérieure des mines de Paris)

Subjects
[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract

International audience

Published
2017

40. Liquid rope coiling in a power-lax fluid: simulation and observation of the structuration at the impact

Author

Soeiro Pereira, Anselmo, Antoniotti, Alexandre, Castellani, Romain, Valette, Rudy, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract

International audience

Published
2017

41. Influence of the polarity of the matrix on the breakage mechanisms of lignocellulosic fibers during twin‐screw extrusion.

Author

Berzin, Françoise, Lemkhanter, Loubna, Marcuello, Carlos, Chabbert, Brigitte, Aguié‐Béghin, Véronique, Molinari, Michael, Castellani, Romain, and Vergnes, Bruno

Subjects
COMPATIBILIZERS, MALEIC anhydride, REACTIVE extrusion, ATOMIC force microscopy, FIBERS
Abstract

In a series of previous papers, models describing the breakage of lignocellulose fibers during melt mixing process were established and applied to predict fiber size changes when compounding composites in a twin‐screw extruder. Different types of fibers were studied (flax, hemp, sisal, etc), but always with the same matrix, namely polypropylene (PP) compatibilized with PP grafted with maleic anhydride (PP‐g‐MA). In the present study, the influence of the matrix was characterized, by comparing the results obtained with nonpolar PP and polar poly(butylene succinate) (PBS) of similar viscosity. For flax and hemp fibers, morphology changes (in length and diameter) were characterized along the screws under various processing conditions (screw speed and feed rate). Whatever the conditions, breakage was more important with the PBS matrix. Moreover, the rheological properties of the composites were also different, indicating specific interactions between fibers and matrices. Atomic force microscopy was used to measure the adhesion between the different matrices and AFM levers functionalized with nanocrystalline cellulose. The results confirmed a better interaction between the nanocrystalline cellulose and the PBS matrix compared to the PP one. [ABSTRACT FROM AUTHOR]

Published
2020
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42. Observation de la coalescence et de la migration de bulles dans un fluide à très faible nombre de Reynolds

Author

Castellani, Romain, Marchal, Antoine, Valette, Rudy, Poulesquen, Arnaud, Centre de Mise en Forme des Matériaux (CEMEF), Mines Paris - PSL (École nationale supérieure des mines de Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Service des Procedés de Décontamination et d'Enrobage des Déchets (SPDE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and MINES ParisTech - École nationale supérieure des mines de Paris

Subjects
[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], [SPI.MECA.GEME]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanical engineering [physics.class-ph]
Abstract

International audience

Published
2016

43. Study of the rheological behavior of plastisol industrial formulations

Author

Abdesselam, Yamina, Agassant, Jean-François, Castellani, Romain, Valette, Rudy, Demay, Yves, Diego, Gourdin, Richard, Peres, Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Jean Alexandre Dieudonné (JAD), Université Nice Sophia Antipolis (... - 2019) (UNS), and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], [SPI.MECA.GEME]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Mechanical engineering [physics.class-ph]
Abstract

International audience

Published
2016

44. Phénomènes d'interactions et d'auto-organisations de nanoobjets fibrillaires dans une matrice polymère

Author

Falco, Guillaume, Peuvrel-Disdier, Edith, Castellani, Romain, Giulieri, Françoise, Volle, Nicolas, Pagnotta, Sophie, Mija, Alice, Alziary - Manuel, Nadine, Laboratoire de physique de la matière condensée (LPMC), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Centre de Mise en Forme des Matériaux (CEMEF), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), SAS PIGM'Azur, and SAS PIGM'AZUR

Subjects
Nanofibre, auto-organisation, huiles végétales, [SPI.MAT] Engineering Sciences [physics]/Materials, sépiolite, [SPI.MAT]Engineering Sciences [physics]/Materials
Abstract

National audience; Le renforcement des polymères est très souvent réalisé par des nanocharges en raison de leursgrandes surfaces de contact, jouant un rôle particulier sur leurs comportements. Parfois de formesanalogues à celles de fibres, ces charges jouent un rôle important dans les propriétés thermiques,mécaniques, optiques ou barrières et permettent de renforcer un matériau à l’aide d’une faibleconcentration de matière.Cette étude s’intéresse à la dispersion de nanofibres de sépiolite, une argile naturelle, dans unematrice polymère. L’utilisation de cette argile minérale est très répandue dans le domaine despolymères [1] du fait de sa forme aciculaire, de son faible coût ainsi que de son abondance. Viadifférents procédés et traitements, nous allons voir qu’il est possible de modifier les mécanismes dedispersion de cette charge au sein d’une matrice polymère et donc de modifier les propriétés finalesdes composites synthétisés. Les résultats obtenus à partir de deux méthodes de dispersion serontcomparés: (i) l’ultraturrax qui permet l’obtention de microdispersions et (ii) la sonification quipermet l’obtention de nanodispersions. La morphologie des mélanges et la qualité de la dispersiondes charges ont été caractérisées par microscopie électronique à balayage (MEB). Les interactionsentre les fibres et la matrice ont été suivis au cours du temps par rhéométrie (suivi des modulesviscoélastiques, et donc de la reconstruction du réseau minéral, après un pré-cisaillement). Lespropriétés thermomécaniques des matériaux composites ont pu être évaluées grâce à lathermogravimétrie (TGA) et à l’analyse mécanique dynamique (DMA).Références[1] Volle, N.; Giulieri, F.; Burr, A.; Pagnotta, S.; Chaze, A. M., Controlled interactions betweensilanol groups at the surface of sepiolite and an acrylate matrix: Consequences on the thermal andmechanical properties. Materials Chemistry and Physics 2012, 134 (1), 417-424.

Published
2016

50. Caractérisation rhéologique et structurale de gels colloïdaux utilisés pour la décontamination nucléaire

Author

Castellani, Romain, Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université de Lorraine, and Lionel Choplin

Subjects
[SPI.OTHER]Engineering Sciences [physics]/Other, colloids, decomissioning, Décontamination, processes, Colloïdes, rheology, Décontamination radioactive, Procédés, gels, Rhéologie
Abstract

During the exploitation of a nuclear plant, or all other installation which uses radioactive materials, maintenance tasks or decommissioning operations are mandatory in order to preserve people health and environment. Among existing processes, decontaminating gels have been development by CEA in order to overcome the drawbacks of the traditionally used methods. These colloidal gels were originally formulated in an empirical way; however, the knowledge of their structures is important as it rules all the rheological behaviors of the material. The way these gels flow is an important parameter to the process and our laboratory measurements can be transposed to the industrial world. Moreover, other composition refinements have been developed in order to extend their field of use and efficiency; Au cours de la vie d'une installation dans laquelle est utilisée de la matière radioactive, des étapes de maintenance, ou bien à terme de démantèlement, sont nécessaires afin d'assurer une protection convenable des travailleurs et de l'environnement. Parmi les procédés existants, des gels de décontamination ont été développés au CEA afin de pallier aux inconvénients des méthodes classiquement utilisées. Ces gels colloïdaux, formulés à l'origine de façon plutôt empirique, ont une structure qu'il convient de connaitre, celle-ci étant la clef de voute du comportement rhéologique du matériau. La façon dont ils s'écoulent est en effet un paramètre important du procédé, et les mesures en laboratoire qui sont effectuées sur ces systèmes permettent d'en améliorer l'implémentation. En outre, de nombreux raffinements du procédé, par le biais notamment d'additifs, en étendent le champ d'utilisation, et l'efficacité

Published
2013

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