Please use this identifier to cite or link to this item: http://hdl.handle.net/1946/3439
This thesis work is dedicated to the study of under-ventilated compartment fires, focusing especially on its most complex and hazardous related phenomenon: a deflagration or rapid combustion called backdraft. In order to predict and mitigate the risk of a backdraft, it is essential to have a good understanding of the gas dynamics which can lead to the ignition and the propagation of the flame, resulting in backdraft.
This thesis work is divided into two parts. The first part introduces the theme of under-ventilated fires and backdraft, describes the means and techniques used during this thesis work, presents and discusses the main results and gives final conclusion and recommendations for further work. The second part contains the research papers written during this thesis work, published in reviewed scientific journals or presented in international conferences.
Computational Fluid Dynamics (CFD) models are shown to be very useful in fire safety engineering, for example to help design modern and safer buildings. In this thesis work, CFD calculations are carried out to estimate the effectiveness of common fire-fighting tactics on backdraft mitigation. Considerable experimental work was carried out as a part of the thesis work and CFD techniques were used to simulate vent flows and other flow patterns in under-ventilated fires. However, the modeling of the incomplete combustion and the extinction of strongly under-ventilated fires is still a challenge for the combustion community.
The occurrence and intensity of a backdraft are directly related to the mixing level and therefore to the properties of the gravity wave. In this thesis work, the combination of analytical, numerical and experimental methodologies gives a good description of the hydrodynamic process prior to backdraft ignition.