Experimental investigation into the flame structure for multiple hydrogen-rich micro-mixing jet flames

Abstract

Micro-mixing combustion is a potential gas turbine combustion technology suitable for hydrogen and hydrogen-containing syngas. The impacts of hydrogen blending ratio and equivalence ratio on flame structure of syngas (a mixture of H₂, CO) were investigated in a lab-scale gas turbine model burner. Flame luminescence and planar laser-induced fluorescence measurements of the OH radicals were employed for quantitative assessment of the flame structure. The flame boundary is extracted by the adaptive threshold method, and the flame wrinkle is analyzed by the probability density function and flame edge node network topology method. The results show that, as the H₂ blending ratio of the hydrogen-rich syngas is in the range of 50%-100%, the flame wrinkle curvature is concentrated near zero, and the convex structures at the flame wrinkles occur more frequently than concave structures. For the hydrogen flames, the node degree distribution of flame edge nodes changes significantly at different times, but the probability density function of node degree at flame front is basically the same. With increasing the equivalence ratio, the distribution of the hydrogen flame edge radius size is more complex, but the node degree reduces. While the equivalence ratio increases above 0.645, the increased turbulence intensity results in a higher probability of the key wrinkles.