Numerical and experimental investigations of swirl-stabilized partially premixed flames using natural gas-hydrogen-air mixtures

A partially premixed swirl stabilized burner is analyzed using experimental and numerical studies. The fuel composition is changed throughout the experiments and numerical simulations. In the experiments, fuel composition is started from pure natural gas, and gradually hydrogen is added to the fuel mixture. The effect of hydrogen addition is analyzed using chemiluminescence imaging. The total volumetric fuel flow rate is kept constant throughout the experiments. The experiments are conducted up to a hydrogen ratio that causes the flame to change stabilization mode from a lifted-off flame to a flame attached to the central fuel pipe below the injection holes. Both lifted-off flame dimensions and stability mode change are analyzed using numerical simulations. StarCCM+ software is used with Large Eddy Simulation (LES) turbulence model, Flamelet Generated Manifold (FGM) combustion model, and Thickened Flame Model (TFM) turbulence-chemistry interaction model.