Hydrogen combustion characteristics in a model burner with a coaxial injector

We have developed a burner for a hydrogen combustion turbine and proposed two kinds of burners, in which the combustion region is separated from the mixing region and in the former H₂ and O₂ are burned in a slightly fuel-rich condition or a stoichiometric condition. We manufactured a small-scale, water-cooled model burner, made of oxygen-free copper, and with two pairs of transparent quartz windows for a flame observation. A coaxial type injector was employed, in which an inner tube (for oxygen) was set inside the recess of the outer tube (for hydrogen). The H₂-O₂ combustion characteristics were studied while changing such parameters as injection velocities, equivalence ratios, and swirl numbers adding to a O₂ flow. The stable combustion region ranged from ṁH₂ = 0.3–1.5 g/s and fr φ = 0.9–2.0. Then H₂-O₂ combustion characteristics in steam, N₂ and Ar were studied to get stable combustion conditions. As a result, we obtained the fundamental design materials for a hydrogen combustion turbine.