Investigation of variable density flow motions between two compartments connected with an open door: application to fire smoke propagation

The thesis deals with fire smoke propagation phenomena for typical nuclear facility scenario: two rooms connected with an open door. The objective is to study propagation phenomena in the final goal of improving the knowledge for safety and proposing data base for code validation. The methodology is based on the combination of three experimental approaches: reduced scale isothermal approach using air / helium gas mixture, reduced scale thermal approach using combustion of small cup of hydrocarbon and large scale approach with fire tests. The study focuses on filling process in the 'source' room, the flow at the doorway and the spill plume in the target room. The filling process investigation shows the influence of enrolments on air entrainment and the effect of thermal losses on the stratification. A coarse description of the flow at the doorway is proposed. The behaviour of the spill plume points out two regimes of spilling, the trajectory characteristics and the location of the impact at the ceiling. Several topics are investigated: the location of high temperature regions, the effect of mechanical ventilation, the effect of the dimension of the doorway, the trajectory of the spill plume, the effect of the convection heat flow. In addition, visualisations of smoke flow at large scale with laser techniques have been performed. (author)