SOFT Optique des systèmes particulaires

Optique des Systèmes Particulaires

Direction : Fabrice OnofriEnglish

Permanents: Séverine Barbosa (MCF-AMU), Fabrice R.A. Onofri (DR-CNRS), Chantal Pelcé (MCF-AMU)

Objectifs :

Nous étudions et caractérisons les propriétés de diffusion et d’absorption de la lumière des particules transportées, transformées ou produites par les milieux diphasiques ou multiphasiques, les suspensions colloïdales et plasmas, etc. Nos activités s’articulent autour du triptyque:
(i) Modélisation des propriétés de diffusion de la lumière de différents milieux chargés en particules (poussières, agrégats, gouttes, bulles, fibres,…), à l’aide de théories électromagnetiques (Lorenz-Mie, Debye, Dipôles,…); d’approximations semi-classiques, physiques et géométriques, ainsi que de méthodes couplées et/ou hydrides du type (Monte Carlo,…)
(ii) Techniques expérimentales de caractérisation optique de ces milieux : spectroscopie d’extinction, diffractométrie vers l’avant, à l’angle d’arc-en-ciel ou critique, mesures angulaires en diffusion statique ou quasi-statique, imagerie classique et hyperspectrale, technique phase Doppler (Dual mode, Dual burst, N-faisceaux, correction des flux, etc.).
(iii) Travaux collaboratifs et de valorisation sur des sujets allant des nano fluides aux suspensions, écoulements multiphasiques, instabilités hydrodynamiques et de fibrage, fluidisation, procédés plasma et tokamaks,…

Mots clefs : Diffusion de la lumière, electromagnétisme, approximations semi-classiques, methodes numériques et inverses;  granulométrie optique, diffraction en champ proche holographie) et lointain (Fraunhoffer, arc-en-ciel, critique), interférométrie (phase Doppler et autres) et Imagerie conventionnelle, spectrometrie d’extinction; nano et mictroparticules, particules, gouttes, bulles, suspensions, plasmas poussièreux, écoulements multiphasiques, instabilités et séchage….

Axes de recherche

Diffusion de la lumière

Caractérisation de particules et systèmes

Valorisation et collaborations

Actualités

10th International Conference on Laser-Light and Interactions with Particles (LIP2014, August 25-29th, 2014, Marseille)
www.lip2014.eu
Contact; download flyer

14ème congrès Francophone de Techniques Laser pour la Mécanique des Fluides (CFTL2014, 15-19 Sept., 2014, Marseille).
www.cftl2014.fr
Contact; télécharger la plaquette

9eme Ecole d’Automne AVFL/CNRS “Techniques Laser pour la Mécanique des Fluides” (eAFVL2013, 8-13 Sept. 2013, Ile d’Oléron).
www.afvl.fr; télécharger la plaquette

  • Onofri F., Barbosa S., “Diffusion de la Lumière (Chapitre 1)” dans Boutier, A (ed.) “Métrologie laser pour la mécanique des fluides: granulométrie et techniques spectroscopiques”, Hermès-Lavoisier, Paris (2012)
  • Onofri F., Barbosa S., “Granulométrie Optique (Chapitre 2)” dans Boutier, A (ed.) “Métrologie laser pour la mécanique des fluides: granulométrie et techniques spectroscopiques”, Hermès-Lavoisier, Paris (2012)
  • Onofri F., Barbosa S., “Chapter I: Basics on light scattering properties of small particles”, in “Laser Metrology in Fluid Mechanics”, Boutier, A (ed.), Wiley-ISTE, London (Dec. 2012)
  • Onofri F., Barbosa S., “Chapter II: Optical particle characterization”, in “Laser Metrology in Fluid Mechanics”, Boutier, A (ed.), Wiley-ISTE, London (Dec. 2012)

Group Optics of Particle Systems (GOSP)

Head : Fabrice Onofri

Academic-Staff: Séverine Barbosa (Assoc. Prof., AMU), Fabrice R.A. Onofri (Research Dir., CNRS), Chantal Pelcé (Assoc. Prof., AMU)
Students(s): Cédric Montet (PhD stud.), Quentin Gaubert (PhD stud.), Mariam Ouattara (PhD stud.)

Objectifs :

Basically, we develop methods to characterize particle & particle systems ranging from multiphase flows, to suspensions or dusty plasmas. Light, as a probing tool, and more particularly the light scattering and absorption properties of small particles, is at the basis of all our activities.
Three main axis are developed : (i) Light Scattering models (i.e. Lorenz-Mie Theory, Debye’s decomposition, Geometrical and Physical optics, Monte Carlo…) for various particles and particle systems (droplets, bubbles, fibers, aggregates,…) ; (ii) Particle and particle systems characterization (high resolution diffractometry and nephelometry in forward, rainbow and critical angle diffraction zones; extinction spectroscopy; phase Doppler interferometry, holography…); (iii) Granted projects and collaborations on subjects connected with nano fluids, suspensions,aerosols and multiphase flows (e.g. instabilities of capillary and viscous jets, glass-fibre drawing; thermosolutal instabilities; gas-solid circulating fluidized beds flows; sprays and bubbly flows; plasma processes and tokamak reactors. This activity is at the the crossroads of the lab’s research axes Divided media and Optical diagnostics”.

Keywords: light scattering, optical & physical optics, electromagnetism, Lorenz-Mie theory; particle characterization, remote sensing; interferometry, holography, diffractometry, refractometry, velocimetry; multiphase flows, bubbles, droplets, capillary & viscous jets, instabilities, suspensions, nanoparticles, dusts, aggregates, plasmas,…

Light Scattering Models

We develop models to solve direct and inverse light scattering problems, for basic purposes, as well as to propose new optical techniques allowing characterizing various particle systems (suspensions, multiphase flows, dusty plasmas,…). Depending of the application considered, and obviously the size range and morphology of the particles, these light scattering models are based on:

  • Geometrical Optics (works fine for large particles and far from caustics and singularities),
  • Physical optics (diffraction at the vicinity of the forward direction, the rainbow or critical angles),
  • Separation of variables based theories (Generalized Lorenz-Mie, Debye, CAM)
  • Numerical methods (as users only, e.g. T-Matrix, Discrete Dipoles),
  • Monte Carlo method (multi-physics approach allowing to account for complex experimental setups and systems).
The animation above illustrates briefly some of the models developped over the years: first order physical optics approximation at the vicinity of the critical angle of spheroidal bubbles [1, 2]; Monte Carlo model for dense suspensions of complex shaped particles within in complex geometry; Debye theory coupled with the Generalized Lorenz-Mie theory to account for some wave effects or constraints [3, 4]; comprehensive library of numerical tools to simulate and analyse the optical structure factor of compex aggregates [5,6,7].

Particle and Particle Systems Characterization

We develop basic experimental setups and experiments to evaluate existing light scattering models and codes. This activity brings also the necessary physical insights  to conceive new physical models as well as to formulate the concept of original optical particle characterization methods (direct and inverse). This experimental work requires precise optical and mechanical setups, as well as various electronic and softwares developpements, e.g.:

  • Multi-angle static and dynamic light scattering techniques: quantitative analysis of the optical structure factor (nanoparticles and aggregates) or the far-field scattering pattern at the vicinity of discontinuities and caustics (forward, rainbow angle and critical angle diffractometry for large bubbles, droplets, fibers, jets),
  • Polarized UV-NIR light extinction spectrometry (LES) for probing nano particles and aggregates at large distance,
  • Interfometry (e.g. phase Doppler) for the characterization of the size, refractive index and homogeneity of large particles,
  • Imaging and image processing techniques (with classical and organic sensors, holographic reconstruction).

The above figures illustrate some of our setups and experiments: diffractometer operating near the critical angle (jets and bubbly flows); Phase Doppler Interferometer with three coherents beams: setup and softwares (version optimized for glass-E fibers); Setup and recorded sample for the rainbow produced by microdroplets under ultrasonic levitation (evaporation of complex fluids); Two totally different multiangle static light scattering setups (for dilute nanofluids and dense fludized beds); Real time extinction spectrum and PSD reconstruction for nano aggregates produced in a dusty plasma ( SiH nanopowder production); Nano-aerosols loop equiped with an extinction setup and a plasma plume generator (remote sensing).

Granted Projects and Collaborations

Actual

  • ANR AMO-COPS: Advanced Methods for Optical characterization of COmplex Particle Systems (with CORIA, CRPP, LMFA)
  • CILAS: Optical sizing of fractal-like aggregates: direct and inverse problem
  • CEA-Marcoule: Experimental characterization of droplets size and interfacial area in liquid-liquid systems using the rainbow diffractometry technique
  • IFP-EN : Optical characterization of the drying of colloidal suspensions
  • PHC Polonium with the Institute of Physics (PAS, Warsaw, Poland)

Former

  • ANR NANOMORPH:  Particle size, shape and concentration of nanotubes/nanowires in liquids (with Arkema, BRGM, CILAS, …)
  • OSEO-OptiPAT : Breaking-down optical approaches for process analytical technologies (with CEA-Liten, Indatech, Isorg,…)
  • NSF-Bulgaria: Advancing Continuum Mechanics Methods by Variational Computational Principles (with IMECH-ABS)
  • ANR CARMINA ( In-situ characterization of micro and nano particle systems: plasmas, suspension, flames… with CORIA, GREMI, IRFM, 2009-2012);
  • FR-FCM-Assoc. Eutatom-CEA/IRFM (In‐situ characterization of dust mobilized in tokamaks)
  • NSF-Bulgaria (Advancing Continuum Mechanics Methods by Variational Computational Principles)
  • Polonium (Optical characterization of nanoparticle systems with CEPM, Wroclaw University of Technology-Poland)
  • Colloids and nanofluids (CILAS,…)
  • Fluidization: PHC AMADEUS (with Univ. technol. of Vienna (AU),…);  Universities of Aalborg (DK) and Chalmers (SE);
  • Combustion: GDR Ariane O2/H2 rocket engine (with ONERA-SAFRAN,…)
  • Dusty plasmas: ANR Galacsy (with CEA, …);  laboratories: GREMI, PIIM, EMPA-Thune (CH); Ruhr-Universität Bochum (GER)…
  • Fusion plasmas: several projects with  IRFM-CEA and FR-FCM.
  • Bubbly flows: PHC Polonium (with CEPM – Wroclaw University of Technology-Poland
  • Multiphase flows: ACI-VITAMA
  • Fiber drawing processes: several projects with Saint-Gobain Recherche, Saint-Gobain Recherche Conception Verrière;Vetrotex International, CERSA;
  • Hydrodynamic and thermosolutal instabilities: several project  with ENIT (TN) IMECH de  Bulgarian Academy (ABS);