The influence of an orifice plate on the explosion characteristics of hydrogen-methane-air mixtures in a closed vessel

Abstract

We reported an experimental study on the explosion characteristics of hydrogen-methane-air mixtures in a closed vessel at normal pressure and temperature. The explosion parameters, such as the maximum explosion pressure, the explosion time, the maximum pressure rise rate and the deflagration index were derived based on the pressure-time evolution. The effect of the blockage ratio as well as the position of the orifice plate on these explosion parameters were analyzed. The results show that the maximum explosion pressure was decreased in the presence of an orifice plate due to the heat transfer to the baffle. At the early stage of the flame propagation, the flame was suppressed. Subsequently, the flame speed was increased at the later stage in some cases. Combined with the various reactivities of the mixtures, the explosion times obtained in all cases were very close. For a given mixture and an orifice plate position, the maximum pressure rise rate and the deflagration index were increased with the increase of blockage ratio. Besides, the maximum pressure rise rate as well as the deflagration index were decreased when the orifice plate was close to the ignitor and oppositely, increased when the orifice plate was away from the ignitor.