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Theses

Étude et modélisation d’écoulements en convection mixte : application au désenfumage naturel de bâtiments

Abstract : This thesis work presents deals with the issue of fire safety consideration in naturally ventilated buildings. The particular case of the interaction between the wind and hot smoke movement is pinpointed. In the first chapter, basics of natural ventilation mechanisms are shown. Then, the analysis of building’s regulations, relating to fire safety and thermal comfort, allows to highlight potential conflicts and normative gaps. Theses gaps and conflicts are illustrated through real buildings feedbacks. The challenge of indoor flow pattern studies for safety purpose is hence underline. In the second chapter, scientific’s barriers in relation with the transitions between existing flow pattern, when wind and buoyancy are opposed, are identified thought a literature review. A scaled experiment is proposed in the third chapter, using density difference between air and helium, to identify internal flow pattern when wind opposes buoyancy. Three stable internal flow patterns are identified. A power law characterizing the transitions between identified flow pattern, involving source Froude number and dynamic pressure ratio between source jet and wind, is found. In the fourth chapter, the identified flow pattern are observed when the tested volume is emptied, and a relation between the initial Richardson number Ri and the characteristic emptied time θ is found. Furthermore, specific behaviour of internal flow, when the volume is emptied, is quantitatively study thanks to a numerical model. In the last part of this thesis, transitions law between internal flow patterns allows to introduce a new wind dependent fire safety index. A methodology is then proposed to both analyse fire safety and thermal comfort in building. The presented method gives the opportunity to avoid conception conflicts underlined in the first chapter of the present work.
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https://tel.archives-ouvertes.fr/tel-02059258
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Submitted on : Wednesday, March 6, 2019 - 2:43:08 PM
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2018lare0027_KJuhoor.pdf
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  • HAL Id : tel-02059258, version 1

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Karim Khan Juhoor. Étude et modélisation d’écoulements en convection mixte : application au désenfumage naturel de bâtiments. Physique [physics]. Université de la Réunion, 2018. Français. ⟨NNT : 2018LARE0027⟩. ⟨tel-02059258⟩

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