Effect of Swirler Configuration on Combustion of Steam Diluted Lean Premixed Methane-Hydrogen Mixtures in a Generic Dual Swirl Burner

Swirl-stabilized combustion of steam diluted hydrogen-enriched methane air mixture help in mitigating flashback and achieving low NOx and carbon emissions in lean premixed gas turbine combustors. Steam dilution reduces the flame temperature and speed associated with hydrogen addition, alters the concentration of active chemical species that forms NOx and allows for operating on high hydrogen content. The effect of hydrogen addition and steam dilution on flow fields, flame stability and NOx emissions can vary with swirl configurations. In this work, we numerically investigate the effects of swirl configurations (co- and counter-rotating) on flame stability and emissions of a dual swirl burner operating on premixed methane-hydrogen-air mixtures. Reynolds Averaged Navier Stokes (RANS) simulation approach employing Reynolds stress turbulence model and flamelet generated manifold combustion model is used to predict the flow within the burner and inside the combustor. Results based on characterization of axial and tangential velocity fields, temperature distribution, turbulent kinetic energy, NOx and carbon emissions are presented. Further, the flame shape is characterized by distribution of OH* and CH* radicals.