Experimental study on premixed hydrogen/air and hydrogen–methane/air mixtures explosion in 90 degree bend pipeline

•Hydrogen–methane/air and hydrogen/air mixtures flame propagation in 90° pipeline.•Overpressure of hydrogen–methane/air and hydrogen mixtures/air in 90° pipeline.•Flame speed of hydrogen–methane/air and hydrogen mixtures/air in 90° pipeline.•Risk posed by hydrogen–methane/air and hydrogen mixtures/air explosion.

Nowadays, hydrogen is being utilized massively in industries as a clean fuel. Displacing of hydrogen due to unique chemical and physical properties has adversely affect on pipeline network, hence increases the potential risk of explosion. This study was carried out to determine the flame propagation of hydrogen/air and hydrogen–methane/air mixtures in pipeline. A 90° pipeline with L/D ratio of 40 was used. Pure hydrogen/air mixture with equivalence ratio, φ = 0.13, 0.17, 0.2, 0.24, 0.27 and 0.30 were used in this work. Different composition of hydrogen–methane–air mixtures were tested in this study i.e. 3%H2 + 97CH4, 4%H2 + 96CH4, 6%H2 + 94CH4 and 8%H2 + 92CH4. All mixtures were operated at ambient condition. The results show that bending is the critical part of pipeline and higher concentration of hydrogen can affect on maximum overpressure, flame speed and temperature rise of both pure hydrogen/air and methane-hydrogen/air mixtures.