Flammability limits of hydrogen/air mixtures

In the framework of nuclear safety related to a hypothetical hydrogen release it is fundamental to assess the risk of explosion according to the initial temperature and pressure. Indeed, among the different combustion parameters necessary to assess the risk of explosion (ignition energy, flame velocity, burning rates, energy release…) the flammability limits are fundamental. They are defined as the lowest and highest fuel concentrations for which a self-sustained flame can be obtained. Near these limits it is also important to identify the type of propagation that will take place depending on different parameters such as the ignition energy, experimental device, phenomena due to buoyancy… The aim of the present work is to identify characterize the type of combustion of hydrogen / air mixtures near the flammability limits for different initial temperatures (25 up 150°C) and pressures (1 and 2.5 bars) relevant with Pressurized Water Reactor conditions.