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Etude et développement de structures fibreuses nontissées dédiées à la filtration de particules fines dans l'air.

Abstract : Nonwoven fibrous media are textile structures currently found in air filtration applications, especially for fine particles below 1 µm. In this field, we need a compromise between filtration efficiency (particle capture) and pressure drop (fluid flow). The nonwovens' structural characteristics are crucial for the final filtration properties. We propose in this study an original approach by developing our own nonwoven filters with production tools close to industry. In this way, we can select structural criteria (thickness, basis weight, fiber type, fiber diameter etc.) that are adapted to the desired air filtration properties. The study of various structural characteristics shows that the most significant parameter to filtration properties is the fiber diameter. When fiber fineness decreases, we improve filtration efficiency but to the detriment of pressure drop. The expression of basis length of fibers has been defined and appears to be a relevant parameter in the description of filtration properties of our nonwoven structures. Packing density also has an influence on filtration efficiency and pressure drop: these two properties increase with packing density. Our study of nonwovens based on blends with different fiber diameters shows that a good filtration efficiency in these samples was conditioned by a sufficient basis length of fine fibers, while the coarse fibers give a structuring of the fibrous media that guarantees a lower pressure drop. The production of nanofibers with the electrospinning process gives samples with a fiber diameter of 250 nm. The improvement of the compromise between filtration efficiency and pressure drop observed is due to higher Knudsen numbers of nanofibers compared to microfiber samples. The modeling of the filtration properties shows in the case of idealized samples (cylindrical fibers, fiber diameter around 10 µm etc.) that theory is in agreement with experimental results. However, the use of fiber blends or fibers with special cross-section induce some limitations to these models. We propose some solutions by taking into account several structural characteristics of the fibrous media to obtain results closer to the experiments.
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https://tel.archives-ouvertes.fr/tel-00474263
Contributor : Julien Payen <>
Submitted on : Monday, April 19, 2010 - 2:00:56 PM
Last modification on : Thursday, December 26, 2019 - 2:52:05 PM
Long-term archiving on: : Tuesday, September 28, 2010 - 12:54:08 PM

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  • HAL Id : tel-00474263, version 1

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Julien Payen. Etude et développement de structures fibreuses nontissées dédiées à la filtration de particules fines dans l'air.. Mécanique [physics.med-ph]. Université de Valenciennes et du Hainaut-Cambresis, 2009. Français. ⟨tel-00474263⟩

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