Hydrogen explosion in ITER: Effect of nitrogen dilution on flame propagation of H2/O2/N2 mixtures

27e Symposium on Fusion Technology / Liège (Belgique), 24-28 septembre 2012

​The present work is a research aimed at acquiring data useful to support the assessment of H₂/O₂/N₂ mixtures risk explosion in ITER. This poster reports laminar flame properties: maximum combustion pressure (P_MAX), deflagration index (K_G ) and laminar flame speed (S_L°) of H₂/O₂/N₂ mixtures over a wide range of initial conditions (XH₂=0.1–0.6 ; N₂/O₂ = 0.66–9 ; T_ini = 303–343 K ; P_ini = 50–100 kPa). This study was performed in a stainless steel spherical chamber (0.056 m³ volume) equipped with an electric central ignition. A high speed imaging system is used to visualize the outward flame propagation and deduce S_L°. The evolution of the pressure inside the vessel during the combustion is monitored. From this temporal evolution of the pressure, P_MAX and K_G are deduced. Laminar flame speeds were evaluated using 3 different detailed kinetic mechanisms from the literature. The comparison between simulated and experimental values was used to select the most suitable one to calculate the global activation energy of these mixtures.