The effect of hydrogen enrichment on the forced response of CH4/H2/Air laminar flames

Hydrogen-enrichment of conventional natural gas mixtures is an actively-explored strategy for reducing pollutant emissions from combustion. This study investigates the effect hydrogen enrichment on unsteady flame response to perturbations, with a view understanding implications thermoacoustic stability. The Level Set Approach kinematically tracking front was applied laminar conical premixed methane/hydrogen/air subjected 2D incompressible velocity perturbations. For levels ranging 0% 80% by volume, resulting heat release rate used generate Flame Describing Functions (FDFs). performed across range perturbation frequencies and at ambient pressure. mean fixed Q?¯=2.69kW equivalence ratio set ? = 1.08 all levels. found shift FDF gain drop-off higher frequencies, which will increase propensity instability. It also reduced effective time delay. Sensitivity analyses 0.8 revealed that changes in were driven predominantly burning speed, insensitive Markstein length.