Effect of hydrogen addition on the structure of a turbulent stratified swirl Methane-Air flame

This article investigates the effect of adding different amounts of hydrogen fractions (on the volume of fuel basis) in an unconfined turbulent stratified swirl methane-air flame. Two different cases have been investigated. In the first case, 20% of hydrogen is added in both inlet slots, while in the second one, 40% is added in the slots. The impact of adding different amounts of H2 is investigated on the flow fields’ characteristics, including velocity, temperature, and OH mass fractions, in the condition of stratification and perfectly premixed. For this purpose, a computational approach using the PaSR combustion model and the SST k-ω turbulence model, has been applied. Results reveal that by adding more hydrogen into the fuel stream, the flame structure changes considerably, especially about the recirculation zone on the bluff body, which shrinks by adding hydrogen. When comparing the stratified and premixed cases, the reduction on the recirculation zone length is more pronounced in the stratified one. In addition, the size of the high-temperature region increases significantly, and maximum temperature rises.