Influence of geometry on flame acceleration and DDT in H₂-CO-air mixtures in a partially obstructed channel

Previous studies of flame acceleration and deflagration-to-detonation transition (DDT) in a partially obstructed channel applying a blockage ratio of 60% and a spacing of 300mm showed that the addition of CO to H₂-air mixtures can have an impact on flame acceleration, DDT and the resulting peak pressures. In this study, the obstacle configuration of the channel is varied to enable further investigation of the influence of CO on flame dynamics. Blockage ratios are set to 30% and 60%, while the spacing between the obstacles is varied between 100 and 300 mm. The test rig is a small-scale six-meter-long channel with a rectangular cross section. The fuel is varied between 100/0, 75/25 and 50/50 H₂/CO. The overall fuel content is varied within the range 15-40vol.-% fuel in air. The flame speeds and dynamic pressures are then evaluated. Limits for DDT in homogeneous H₂-CO-air mixtures are presented with regards to fuel composition and fuel content. The results extend the existing data on flame acceleration and DDT provided by Veser et al. (2002) and can be used to validate numerical frameworks.