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Capture, par mousse aqueuse, de particules micrométriques dispersées par explosif. Étude expérimentale et numérique

Abstract : In order to improve the protection of goods and persons, the CEA (The French Alternative Energies and Atomic Energy Commission) is interested in aqueous foams for their ability to mitigate a detonation. The objectives are, on one hand, to mitigate the blast effects related to the detonation of an explosive device and, on the other hand, to capture the potentially harmful micrometric solid particles that can be emitted. Aqueous foam is a two-phase medium, assemblies of gas bubbles, encapsulated in a matrix of liquid films and nodes, called Plateau Edges. We are interested in so-called dry foams, i.e. with a volume fraction of liquid phase less than 5 %.The aim of this thesis is to understand the phenomena underlying the second problem, by carrying out experimental campaigns, and to develop a numerical tool to simulate them. The thesis work is divided into two main parts. The first concerns the dispersion and the slowing down, in intact foam, of micrometric particles dispersed by mechanical impulse. First,a numerical model of slowing of micrometric particles in this medium has been developed. In a second time, experimental campaigns carried out, one in a shock tube at a CEAs facility, and the other, in an electric plasma gun at the Pprime Institute, highlighted the attenuator character of the foam, in terms of particle dispersion. They are also used to formulate drag laws in this medium. The second part deals with the capture, by the aqueous foam, of micrometric particles dispersed by explosive. Two campaigns were conducted for this purpose, at CEA / Gramat, to quantify the rate of particles captured by a foam confinement. Thus, a parametric study was carried with various explosive charge masses, particles masses, particle sizes and aqueous confinement sizes. These results attest to the efficiency of this two-phase medium in the capture of micrometric particles. The comparison of these experimental results with those resulting from a two-dimensional multiphasic Eulerian code, developed in parallel, made it possible to ascertain the aptitude of this code to predict, not only the phenomenology of the blast waves in the presence of particles, but also the dispersion and the capture of these particles by aqueous foam.
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Maëva Mikart. Capture, par mousse aqueuse, de particules micrométriques dispersées par explosif. Étude expérimentale et numérique. Autre. ISAE-ENSMA Ecole Nationale Supérieure de Mécanique et d'Aérotechique - Poitiers, 2019. Français. ⟨NNT : 2019ESMA0022⟩. ⟨tel-02867899⟩

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