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Experimental study and modeling of hydrogen combustion in a flammable atmosphere in the presence of water drops

Homan Cheikhravat, doctorate of University of Orléans, 260 p., defended on the 25th september 2009

Document type > *Mémoire/HDR/Thesis

Keywords > suspended sediment, cutaneous syndrome, AREVA NC

Research Unit > IRSN/DSR/SAGR

Authors > CHEIKHRAVAT Homan

Publication Date > 25/09/2009


This thesis is part of safety studies on Pressurized Water Reactors for nuclear power plants. Scenarios including a release of hydrogen predict to trigger spraying in order to reduce the pressure and collect the aerosols towards the bottom. However spraying involves lowering the temperature and, consequently, the content of water vapor initially sufficient to render the atmosphere inert. The purpose of this thesis is to study the desinerting conditions of premixed hydrogen / air / water vapor in presence of fogs and then to analyze the interaction between the water spray and the f1ame which can initially be laminar or turbulent. For this purpose two facilities have been designed: a sphericat one of 56 L with central ignition that can be heated to 200°C and a large one optimised for flame acceteration (ENACCEF). With these toots have been determined the f1ammabil1ty limits of H2/air/water vapor as a function of pressure and temperature, the behavior of flames close to the limits, the effect of sprinkling on desinerting and finaUy the interaction between the flame front and the droplets considering different mean droplets sizes. The influence of a hydrogen concentration gradient on the acceleration criterion and the role of sprinkling on the propagation of a turbulent flame have also been studied. It appears that the spray can cause not only desinerting but also be ineffective in extinguishing the flame and, in sorne cases, can even increase the turbulence rate and consequently the flame acceleration process.

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Ahmed Bentaïb, the thesis supervisor
Claude-Etienne Paillard, the thesis director

More informations

Thesis report


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