Effect of Swirler Configurations on Combustion of Humidified Lean Premixed Methane-Hydrogen Mixtures

In the present work, we investigate effects of variation in swirler configuration (co- and counter-rotating swirl flows in a dual swirl burner) on isothermal and reacting flow fields and flame structure when the burner is operating on steam-diluted premixed methane-hydrogen-air mixture at ��=0.9. Reynolds Averaged Navier Stokes (RANS) simulation with the SST ��−�� model and Flamelet Generated Manifold combustion (FGM) model are employed to predict the flow field and combustion. We present the results based on the characterization of the turbulent flow field in the nozzles and the combustor, temperature distribution, flame structure, NOx and CO emissions. The counter-rotating swirler flow fields show the presence of high turbulence in the shear layers which enhance the mixing of incoming reactants and hot gases in the recirculation zones thereby stabilizing the flame inside the combustor. We observe the existence of a shorter and compact M-shaped flame attached to the center body of the burner in case of counter-rotating configuration with a small NOx emissions reduction of 5%