The influence of methane addition on the propagation of hydrogen-methane-air detonation in partially confined geometry

摘要

The aim of this study was to perform the experiments of detonation propagating in stoichiometric hydrogen-methane-air mixtures in partially confined geometry. The experiments were done to examine the influence of the methane fraction in fuel on the ability of detonation to propagate. Four types of gaseous mixture composition were used: 0%, 2.5%, 5% and 10% of methane in fuel. The critical height h~* was found for each mixture. Furthermore, by using the smoked-foil technique the detonation cell sizes λ were measured and the correlations h~*/λ were calculated for each mixture. The results showed that detonation of hydrogen-methane-air mixture may propagate in partially confined geometry only when the channel height is at least equal to 1 cell size which is similar to the condition for planar detonation propagating in closed, rectangular channel. The research showed high influence of the boundary dividing the flammable layer from the air layer.