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Granulométrie de particules fines en suspension chargée par mesures de rétrodiffusion de la lumière‎. Application à l'étude de l'agglomération d'une suspension de dioxyde de titane en cuve agitée

Abstract : In the first part of this work, the development of a particle sizing probe exploiting light backscattering is shown. Measurements of the backscattered light intensity covering a large range of particle diameters (0,2 µm to 56 µm), relative refraction indices m (1,09 to 1,94) and solids volume fraction Φ (10-6 to 0,5) have been carried out. Experimental results are compared to three different theories: the single backscattering theory describes backscattering in dilute suspensions, the diffusion approximation of the radiative transfer theory can be applied to concentrated suspensions and the statistical Monte Carlo method to all suspensions. It is demonstrated that the backscatter probe allows to determine a mean particle diameter in concentrated suspensions if Φ and m are known. The measuring range is about 0,03 µm to 10 µm for the partic1e diameter and depends on Φ and m. The second part of this work is devoted to the improvement of knowledge about fine particles agglomeration in turbulent flow. To this aim, aggregation kinetics are investigated over a large range of volume fractions (2°10-6 to 5°10-3) in a stirred vessel. Two different in situ particle sizing methods are used: Turbidimetry and light backscattering. Analysis of experimental data showed that growth of aggregates in the stirred vessel is limited by shear: Aggregation proceeds until a stationary state is reached that corresponds to an aggregate size limit. The proposed model for the aggregation - fragmentation process permits to quantify the influence of the volume fraction and the shear rate on aggregation kinetics and aggregate structure.
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https://tel.archives-ouvertes.fr/tel-00836784
Contributor : Andrée-Aimée Toucas <>
Submitted on : Friday, June 21, 2013 - 2:59:41 PM
Last modification on : Wednesday, June 24, 2020 - 4:18:31 PM
Long-term archiving on: : Wednesday, April 5, 2017 - 1:38:20 AM

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  • HAL Id : tel-00836784, version 1

Citation

Christoph Tontrup. Granulométrie de particules fines en suspension chargée par mesures de rétrodiffusion de la lumière‎. Application à l'étude de l'agglomération d'une suspension de dioxyde de titane en cuve agitée. Génie des procédés. Ecole Nationale Supérieure des Mines de Saint-Etienne, 1999. Français. ⟨tel-00836784⟩

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