Effects of hydrogen addition on the stabilization of lean premixed swirl flames

This paper described an experimental study on the effects of hydrogen addition on the stabilization of ultralean premixed CH4/H2/air flames. The flames were stabilized with a bluff-body and swirl burner. Flame structure and flow characteristics were investigated with simultaneous measurements of OH-PLIF and PIV. It is observed that, the hydrogen addition promotes the flame towards the main flow and the direct distortion from shear layer vortexes is decreased. The flamelet conditioned straining shows different patterns of flow shear forces. Especially, the resistance to the straining near flame attachment with hydrogen addition is probably the vital step for the hydrogen to stabilize the lean flames.