Acoustics measurements in a lean premixed combustor operated on hydrogen/hydrocarbon fuel mixtures

In this study, acoustics and emissions measurements in hydrocarbon flames enriched with hydrogen were obtained for a range of operating conditions. Methane and propane fuels enriched with up to 40% hydrogen (by volume) were used. Fully premixed reactants were burnt in an atmospheric pressure, swirl-stabilized combustor replicating typical geometric features of land-based gas turbines. Acoustics data indicated an increase in the total sound power with an increase in the adiabatic flame temperature. Hydrogen enrichment of methane produced higher sound levels as compared to non-enriched methane with a single frequency band around 450 Hz. Hydrogen-enriched propane flames had lower sound levels, with multiple frequency bands appearing on an intermittent basis. Results suggest that the changes in the combustor dynamics should be considered together with the known benefits of hydrogen addition, i.e., the extended lean blow off limit and lower nitric oxide and carbon monoxide emissions.