Laminar flame velocity determination for H2-air-steam mixtures using the spherical bomb method

In the framework of the new design of nuclear reactor power plant, the hazard due to the presence of hydrogen must be taken into account. More precisely, a mixture of hydrogen, water vapor and air can be formed inside the nuclear power plant building. In order to model correctly the flame propagation in such complicated environment, one of the fundamental input data is the laminar flame velocity of these diluted mixtures. It is needed then to determine the laminar flame velocity of lean hydrogen air flames diluted or not by steam. The present work reports experimental results on the determination of laminar flame velocities of hydrogen - air - diluent mixtures initially at 100 kPa and for 2 different initial temperatures 298 and 353 K. The diluent was water vapor or a mixture containing helium and carbon dioxide. The data obtained in this study are compared with the literature ones. The experimental setup consists of a spherical bomb coupled to a Schlieren system and a high speed camera. The effect of the stretch on the flame velocity is characterized for all the investigated mixtures. Computed laminar flame velocities are obtained using PREMIX and CHEMKIN codes. Two different kinetic mechanisms are used, and the computed values are compared to the experimental ones. (authors)